Archives for January 2016

12 Tips for Winterizing Your Home

It is the season to be jolly, indeed, but not necessarily about the cold that’s slowly creeping up through all the nooks and crannies of your house. The winter solstice is upon us, marking the shortest and darkest day, so we need to turn the thermostat or the heating system up. That will surely reflect on your bill, as it did in all past winters. But not necessarily this one, because we’ve got 12 amazing tips for winterizing your home, so that you can be productive, eco-friendly, save energy and, ultimately, money.

1. Upgrade your thermostat

The first stop on the way to getting winterized is the thermostat. What you can do about it is to either replace it with a programmable one or upgrade it if you can. You will find that this measure is quite needed and it will save you a lot of money and energy. The idea behind the change is to basically have the programmable thermostat turn off or lower the heat when nobody is at home or when you are all on vacation and it’s not needed.

2. Windows

The primary way in which heat leaks out of the house is via the windows, which are not always air tight. Wooden windows are usually the leaky ones because wood is an organic material which expands from the heat in the summer and from water like rain and snow and contracts from the cold. The only thing is that when it does contract, it never comes back to its exact initial shape and that’s when the leaks occur. Here are some more tips:

Replace all the old windows. It might be pricey at first, but the investment will be worth it in time;
Use clear plastic, caulk or even bubble wrap to seal of all the windows (and patio doors while you’re at it);
Uncover all the windows of the house that are facing south so that you can benefit from the full heat of the sun;

3. Using nature

You can plant evergreen trees close to your house as a way of shielding it against the wind, rain and snowstorms. It’s a natural and simple solution to a big problem and it will help more than you think. In wind and snowstorms your house’s walls get cold really fast and your heater has to work much more than normal in order to keep them warm. You can help it out by protecting them from the storms. If you live near the park, your location is ideal.

4. Rework the chimney

If you’re using a fireplace, then your chimney is completely necessary. However, a chimney doesn’t just release the smoke out into the outdoors, but also a good part of the resulting heat. Therefore, one solution to this problem is to consider adding an insert which will divert most of the heat towards the inside. A good thing here is to make sure you contract the best and most experienced installer you can find. It will cost you a bit more, but fireplaces and chimneys are not to be toyed with, as you’re preparing for the winter.

5. Draft snakes

You might remember seeing these particular items in your grandma’s house. That’s because they first appeared during the Depression era, as a great way of reducing energy waste. And guess what, they’re back. Given the fact that heating is so expensive these days, this method of keeping the hot air in for longer periods of time and reducing drafts underneath doors or at the bottom of windows is back in. You can craft some very fancy ones yourself, even in the Yule spirit. You can also make them with your children, as a cute and fun DIY project.

7. Ceiling fans

Another trick you can use is to turn the direction of your ceiling fans. The rule is as follows: a counter-clockwise rotation will produce cold air and a clockwise-rotation of the ceiling fan will produce warm air. According to some recent studies, utilizing this method will actually help you cut the heating costs with as much as 10 per cent. Only remember that the ceiling fan works on electricity, so don’t abuse it. Because what you save on gas, you might end up paying for electricity.

8. Insulation

One of the most obvious solutions on the subject of how to winterize a house is insulation. You need to know a couple of things here. If your house doesn’t have it, you need to insulate it now. If it has it, check to see how old it is. Insulation wears off in time, gets wet or acquires small empty gauges inside the material itself, which will eventually allow the hot air to leave the house and the cold air to permeate it. Therefore, the best solution is to simply load up on insulation as much as you can. Add more in between your walls, to the attic floor, which means your ceiling and to the basement ceiling which means your floor, so that the temperatures inside the house remain constantly toasty.

9. The plumbing

There are a few things you can do with your plumbing in order to make sure you don’t waste any heat through them:

Insulating the water pipes around your water heater is a good idea, so that you can then set it to “warm” instead of “hot, because the pipes are not losing any heat;
Insulate all the water pipes that run through cold areas of the house. When that happens, the water gets colder;
Insulate all the cold water pipes so that they don’t freeze over the winter;
Replace the caulking around your bathtub and your shower.

10. Checking the house

Houses get old, the same as people and they need some work done from time to time, especially in winter. The cold air can come in through many unexpected places, so here is a checklist for you to consider:

If your house is made of bricks, you should check the mortar, because it might have cracks in it;
Sometimes shingles can fall off or get worn and you won’t even notice, but that’s a major leakage point for heat during the winter. So make a routine check before the first snow falls, when you can still see the roof.
You can also check the foundation and seal away any cracks you might find there.
Check to see if the garage is not too cold or draughty and causes temperatures to drop in adjacent rooms or allows the cold air to come in.
Seal off any vacant rooms in your house and stop using them for the winter. There’s no need to heat them up.
Use the house kitchen wisely and prepare meals during the day. Turn down the thermostat and let the heat from the ovens warm up the rooms. This will save a good couple of hours, until the food is cooked and all the residual heat is gone.

11. Warm clothes

Of course, warm clothes do not mean wearing boots and coats inside the house, but you should always wear socks and slippers, because if your feet are warm, so will the rest of your body be. Second of all, it’s not a very good idea to crank up the thermostat so high as to be able to walk around in shorts and a t-shirt. Not only because of the high consumption of heat, energy or gas, but for your health as well. Doctors do not recommend spending the winter months continuously moving from the bitter cold outside to the blazing heat inside. Ideal temperatures should be kept at a decent level, and you should be able to wear a sweater inside.

12. The A/C unit

Winterization is the moment when you can get rid of it. Not permanently, but, since you won’t be using it in winter time, you can remove it from the window and seal off all the holes and cracks. The idea behind this is that, usually, A/Cs are not fitted perfectly into walls or windows and they have a lot of small places through which cold air can get in. Another thing you can do about the A/C unit in order to winterize your home is to cover it with a tarp, if you don’t want to put it away for the winter. The US Department of Energy says 5 to 30 per cent of all the energy is wasted away via drafts every year. Which makes drafts the number one enemy.

Here are your top 12 winterizing tips and pieces of advice on how to keep your house warmer this year without adding anything to your bills. And although not all of them might be for you, be on the look-out for signs that your house could use some help when it comes to heating. Also, remember you’re not only doing yourself and your family a favor, but the environment also. There’s no need to turn to the solutions they’re selling and advertising, like adding more heaters. The less energy you use, the greener you are.

Image Sources: 1, 2, 3

All You Need to Know and More about Make Up Air Units

Building proprietors, managers and home owners alike find the need for high indoor air quality rocketing to the top of their priority list as times goes by and requirements become higher and higher. Here is a guide explaining what make up air units are, when can they be used and if it’s the right choice for you, in order to help you decide if you should get one or not.

What are make up air units?

By definition, they are units meant to supply conditioned air, whose temperature and humidity is completely controlled, into a building, in order to replace the air that has been removed by the exhaust systems or by combustion. Their main quality is that they bring fresh outside air through their ventilation heating or cooling equipment, rather than recycling or recirculating the already existent one.

Does it make sense for you to use a makeup air unit?

Usually these mechanical air providers are used by big buildings, like office spaces or apartment blocks, which need to be zoned. For buildings with such purposes, make up air units are very attractive because zoned energy use is very efficient and will give everybody the chance to control their environment, temperature and humidity.

This basically means that every apartment owner or every member of the staff with his own private office will get the chance to use energy, heating and air supplies as they see fit. It’s also very attractive cost-wise. For example, building owners who rent out their lodgings use it to hook and reel in their tenants, by presenting them with this option, instead of having their temperature and air regulated for the whole building. It’s also extremely efficient cost-wise, because a tenant can always turn it down or turn it off altogether if they feel the need and reduce costs significantly.

Makeup air units are also used by buildings such as hospitals, meaning construction structures that cannot reuse the air inside a room. Hospitals have the greatest need for fresh air, probably, of all buildings and this is why they normally go for makeup air units. Nothing should contaminate their air and make people sick. But there are other types of buildings which use it as well, such as paint shops and factories or restaurant kitchens, which, again, cannot afford to recycle the air inside.

Therefore, if you find yourself in one of these situations or have such a project in mind, then a makeup air system is definitely for you. However, if you’re keen on it, you can also use it inside your personal home. If, for example, you cook a lot and you have a big kitchen and it needs kitchen ventilation or if have toddlers around the house and need to refresh the air as often as possible.

However, it was not designed for use in your car. You can use it if you have a spray booth, you can also purchase the small or mini version of it, which can be designed as portable, like the Soleus model. They are not very loud, they come with special installing kits and plans and they can also be used in residential areas, as they have kitchen ventilator options. Make sure to follow the regulations.

Location

Makeup air conditioner units are often associated with rooftop units and that’s why people tend to believe that they should be placed on the roof, but that’s not true. It only happens because they are quite large, having also compressors, controllers, a pump, a gas lantern, vents and an exhaust tank. You can also place it in a mechanical room, if you so see fit. Actually, in most hospitals, they are placed in such special designed rooms, where they can be accessed a lot more easily and quicker than on the roof. In case of emergency, a specialist or a mechanic enters the room and fixes the unit instead of climbing to the roof. It’s also easier when it comes to cleaning it, as it is done with a brush.

Budgets and prices

First thing you have to understand about makeup units is that the price is based on the design and model. Therefore, before deciding to buy a machine, you must take into consideration what goes in each of them. Normally, the usual design cost is based on the ‘per square foot of space’ system. Historically, the grounds for that were represented by standard unitary equipment and very little or no outside air at all. Therefore, when your ventilation requirements ask for a dedicated unit, that’s when the cost per square foot will increase, at least on paper. Deals can, of course, be made.

What this basically means is that you need to do some research and be very well informed about the design, so that you can plan your budget accordingly. But, indeed, tradeoffs can be made and you can also analyze some competing system types so that you can see which one better suits your needs and/or your budget.

Also, take into consideration the first costs as well as the operating costs, when thinking about prices and budgets and plan accordingly. A good idea is making your purchase from specialized sellers, such as Modine, Aaon, Cannon Fabrication, Inc., which produce rooftop accessories, or Mobile Air and have specialized officers to come mount them.

Why is air replacement necessary?

Some might think that simply ventilating a space is enough, but that is not always the case. Depending on the activity performed inside, its size and its requirements, a makeup up air unit which replaces air might be necessary for the following reasons:

So that exhaust hoods must always operate properly. An exhaust hood, also known as extractor hood or basket or, more commonly as a cooking canopy is a type of device that has a mechanical fan built in, which is plug based. It usually hangs above your stove in the kitchen and it’s used to capture and remove airborne grease, hot dry air, fumes, gases, smoke, water vapors, odors, steam and heat caused by cooking on the kitchen stove. Some are designed as easy fresheners, so that they bring in fresh air from the outside, others recycle the air while in traffic, filtering it for grease and bad smells at the same time, before reintroducing it into the room. However, kitchens are not the only place you can find them. They are also components of the makeup air unit and work pretty much in the same way. And it’s very important that they work properly. If there isn’t enough makeup air and there is too much negative air pressure, that can lead to static pressure, which the fans will need to overcompensate. What this does is cause a diminishing of the “cubic feet per minute” air coming from the exhaust fans. This will cause a lot of unwanted negative air flow pressure.

To eliminate all cross drafts which run at high speeds in the rooms between doors and windows, no matter the time of year – this process is linked to the one above, meaning that cross-drafts depend very much on the quantity of negative pressure created. If there is a lot of it, then the drafts can be substantial. In turn, drafts interfere with the proper functioning of the exhaust hoods. But, the main negative thing that can happen is the fact that, if you don’t solve your cross drafts problem, they might carry contaminated air from one space to another. This makes for a very serious thing if, for example, we are talking about a hospital, where you cannot have infected air dispersing randomly between sections or, if you are running a restaurant and the smell of cooking food invaded the actual dining rooms. It’s the same thing with paint factories, where fumes from drying paint can cause serious damage or with construction sites where the dust and tiny debris particles can float back into clean rooms.
To make sure natural draft stacks operate fluently. The stack effect basically means air movement inside and outside of buildings, due to air buoyancy, which happens because of the different densities inside and outside air have. If the stack effect grows in intensity, so will the buoyancy. It’s very important because it is known to be the cause of several fires of great force, like the King’s Cross Fire. This is the main reason why an air replacing unit is so necessary. It removes combustion products such as carbon monoxide, it keeps the pilot light in burners alive, or it announces via its horn that it’s out, it’s a temperature controller and it regulates corrosion damage in stacks.
It’s also necessary in order to reduce cold drafts intake, which can cause serious discomfort to people and kids. By means of consequence, when the cold downdrafts are reduced or eliminated altogether, the temperature rises and money are saved as far as heating and energy are concerned.
To eliminate the different pressures related to doors. One of the reasons doors are usually very difficult to shut or open has to do with high pressure differentials. This can cause injuries and can also be a safety hazard for workers.

Here are the things you need to know about air makeup conditioning units. Remember to consider your budget first as well as your needs and all the safety reasons they involve. All these things will help you decide if this is the best solution for your space.

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Air Conditioner Condenser Unit 101

Condensers can be found in any kind of mechanisms that imply heat transfer. They are used for condensing substances from a gaseous state to a liquid state through a cooling process. When the change happens, the substance gives up its latent heat, which is transferred to the condenser coolant. Condensers come in a wide range of designs, varying in size. Small condenser units are usually used in residential areas, while large units are needed in the pharmaceutical or agricultural processes. Even your home refrigerator has a condenser that helps it evacuate the heat that has been extracted from within the unit. Condenser units are also used in the industrial chemical field (for example in steam power plants or distillation), in air conditioners and in various heat exchange devices. The great majority of conditioner condensers will use the surrounding air or the cooling water as a coolant agent.

Types of condensers

Condenser units have various uses and can be implemented in a number of devices, carrying out different processes.

Surface condensers are made out of a tube heat exchanger and a shell, which are connected to the outlet of steam turbines. Most of the times, this device will use cooling water, which will flow through the tube side, allowing the steam to enter the shell side. This is the place where condensation takes place on the outside of the heat transfer tools. The condensate water will drip down, collecting at the bottom, in what is called a hotwell, a built-in pan. Generally, the shell side will operate at a partial or complete vacuum, which is produced, most of the times, by air ejectors.
Industrial distillation processes will use large condensers to cool down distilled vapor, transforming it into liquid distillate. As a rule, the coolant will flow through the tube side, while the distilled vapor will pass through the shell side and the distillate will collect or will flow out the bottom side.
Condenser units are employed in central air conditioner units. These have heat exchanger sections, which are in charge with cooling down and condensing the incoming refrigerant vapor, transforming it into liquid. An air conditioning condensing unit also has a compressor, which raises the pressure within the refrigerant and passes it along. A fan is used for blowing air via the heat exchanger, in order to cool down the refrigerant inside. Here is how the configuration of an AC condenser looks like: the heat exchanger will wrap around the unit’s sides. The refrigerant will go through several tube passes, all of which are surrounded by hear transfer fins, which allow cooled air to move inside the unit from outside. The motorized fan within the condenser will blow the outside cooling air in with the help of the heat exchange section that can be found at the sides and on the top side. A home condenser unit is usually placed on the outside of the building, and tubes are used to connect the building to the unit. One tube is used for the vapor refrigerant, which enters the device, and another one for the liquid refrigerant that leaves the device. The fan and the compressor need an electric power to function.
Direct contact condensers use vapors that are directly poured into the liquid. The vapors will lose their latent heat, and, as a consequence, the vapors will transfer the heat into the hot liquid. The liquid and the vapor are the same kind of substance in this particular type of condensation.

Other examples of condensers

HVAC (heating, ventilation, and air conditioning) use condensers to a large extent. There are three types of condensers employed in HVAC systems.

Evaporative condensers are not among the most popular choices out there. These can be installed outside or inside a building, operating at a low condensing temperature. This type of condenser is most of the times installed in large commercial air-conditioning units. While they get the job done, they are not the most efficient ones on the market.
Water cooled condensers are on the pricey side in the condensers’ market, however, they are the most efficient ones out there. They call for regular maintenance and they are usually installed for swimming pools. Water cooled condensers need a cooling tower in order to conserve water. Water treatment and makeup water are a must if you want to keep corrosion and algae at bay. You can choose from three types of water cooled condensers: shell and coil, tube in tube and shell and tube.
Air cooled condensers are generally installed on the outside of the unit, ejecting heat to the outdoors. Easy to install, air cooled condensers are commonly found in upright freezers, refrigerator and in air conditioning units. What makes this type of condensers easy to manage is that it doesn’t take a lot of time or effort to clean them. A clean air cooled condenser is essential for optimum performance.

A C condenser

Air cooled condensers are generally used for residential AC systems. This type of devices include earth cooled condensers and combinations of water cooled and air condensers. Using outdoor air to reject the heat absorbed by the unit from the indoor air, air condenser units comprise a fan blade, a motor, coils and a compressor. The job of the condenser fan is to increase the capacity of the unit to reject heat.

Acting as heat exchanger devices, air conditioner condensers are similar to evaporators. The condenser unit will take in the high temperature and high pressure refrigerant gas from the compressor, turning it into high temperature, high pressure liquid refrigerant. The entire process behind air conditioner condenser units is transforming vapor refrigerant into liquid refrigerant. The refrigerant will undergo three essential changes:

The compressor will produce a hot vapor that needs to be de-superheated and brought to vapor saturation point. The de-superheated process involves getting rid of the sensible heat within the refrigerant that is under the temperature of the refrigerant.
A blend of liquid or gas refrigerant can be found in the middle of the condenser, the place where the refrigerant vapor has to transform into liquid refrigerant.
The refrigerant has to reach a temperature under liquid saturation point.

Air conditioner condenser unit maintenance

As with any other HVAC device, cleaning, maintenance and regular repairs are key to preserving the longevity of the device. Condenser units are no exception. Regular maintenance is not rocket science, it doesn’t have to be done too often and can save you a lot of money in the long run. The task can be completed in less than an hour and it is bound to increase the efficiency of your AC condenser unit.

Neglecting to clean your condensing units for a year translates into clogged cooling fins, a lot of debris and dirt. As a consequence, your AC isn’t doing a proper job at cooling down your entire home, like it used to do last summer. What is there to do? Before you schedule a pricey maintenance appointment, there are some steps you can perform to de-clog, clean up and increase the performance of you air conditioning unit. Of course, you won’t be able to check the coolant level, but you can save a hundred dollars by clearing out some dry leaves. These procedures apply to most air conditioning devices out there and you need only the instructions manual to figure out the trickier parts. However, don’t neglect calling in a technician every couple of years for a thorough investigation.

The first step is turning off the power. This is usually done by turning its switch to the OFF position or pulling out a block. If you’re not sure how to turn off the power, you can completely shut down the AC from the electrical panel.
Use a vacuum and a soft brush attachment to get rid of any dry leaves, debris or grass clippings from the fins. You should also get rid of the grass and weeds surrounding the condenser.
It’s not uncommon to notice bent fins on close inspection. These could hinder your air conditioning from working properly. Use a knife to realign the fins, but be careful not to insert it more than half an inch inside the unit.
Unscrewing the grille, gently take out the fan and clean it and the interior with a cloth.
The fins can now be cleaned with a hose nozzle, from the inside out.
Reinstall the fan and get ready to restart the unit. Head to the thermostat and switch it to off. Next up, turn the power back on, but allow the unit to sit for a day, giving the heating element of the compressor enough time to warm up the internal lubricant. After 24 hours pass, you can turn the thermostat on to the cool setting again.
For cleaning the indoor unit, you’ll want to turn off the power or shut it down completely from the main electrical panel. Only then you can pull out the filter and change it if it’s the case.
Vacuum inside the unit and lubricate the ports with four or five electric motor drops.
The drain tube can be cleaned with a water and bleach mixture poured into the tube.
Clean out the drain port to get rid of debris using a pipe cleaner.
After reattaching the drain tube, you can turn the power back on.

Image sources: 1, 2, 3.

BTU Made Easier

The abbreviation for the British thermal unit, BTU is a unit of work that is the rough equivalent of 1055 joules and 252 heat or little calories. What is BTU? Used in the United States and sometimes in the United Kingdom, the British thermal unit stands for the amount of thermal energy that is required to increase the temperature in one pound of water by one degree Fahrenheit. The foot-pound-second system is an English system that uses the BTU, while other countries employ the International System of Units, which uses joules. BTU is also known as Btu or B.Th.U.

Every combustible material has a British thermal unit rating. To answer the question what is a BTU, consider that a pound of burning wood will generate around 7,000 British thermal units, a gallon of fuel oil will generate 140,000 BTU, while a gallon of liquid propane will produce roughly 92,000 BTU. Wondering about bigger BTU generators? A barrel of gasoline is able to produce 4.35 million BTU and a ton of coal produces 20 million BTU. Despite being called the British Thermal units, this measuring non-metric unit is more used in the United States and Canada than in the United Kingdom. In the countries that employ the Btu, this unit is also used for measuring natural gas prices. One cubic foot of natural gas equals 1,034 Btu units.

Let’s look at a specific example: if you want to boil one gallon of water that has 60 degrees Fahrenheit, you will need approximately 1,200 BTU to bring the water to a boiling point, which is 212 degrees Fahrenheit.

At the same time, the British thermal unit is used for quantitative specifications regarding the energy transferring and producing attributes of cooling and heating units, like ovens, refrigerators, air conditioners and furnaces. The computer equipment’s heat output is usually specified in order to be taken into account when technicians set out to plan the climate control system within a house or a building. Expressed in BTU per hour, the output of computer device heat is the equivalent of one watt of heat dissipation.

BTU, BTU / Hr, Input BTUH, Output BTUH, MBtu

When discussing heating a building, the BTUs will describe the heat that is produced by the fuel or energy, which can come from various sources: LP gas, electricity, natural gas or oil. When talking about cooling a building, the rated capacity for the air conditioning unit or the heat pump will be expressed in BTUs. This refers to the removal of a given amount of heat from a room.

BTUH, BTU / Hr or British Thermal Unit per hour refers to the number of BTUs of energy that are generated (for heating units) or removed (for air conditioning units) in an hour.

Sometimes, heating, ventilating or air conditioning units will display two BTU capacities on the appliance label. The first one is Input BTUH, which refers to the energy used up by a heating or cooling system and which is measured per hour in thousands of BTUs.

The Output BTUH points to the heat output or cooling capacity from the cooling or heating unit. This will be measured in thousands of BTUs/ hours and sometimes it will be abbreviated as MBTUH. Theoretically, this is the maximum capacity for cooling or heat output that the system will be able to produce. However, you should always take into account system losses. This means that the actual heat and cooling capacity to be delivered into a room or a building might be lower because of the distribution system losses. As a rule, the output BTUH will always be smaller than the input BTUH since the heating system will never be able to work at one hundred percent efficiency.

MBtu is described as one thousand BTU. Other common abbreviations include mBtu, MMBtu or mmBtu. The “M” is presumed to stand for the Roman numeral system, where this letter signified one thousand. In this context, MMBtu would be rendered incorrect, since it would stand for two thousands. However, MBtu is also mistaken for the SI “M” prefix that stands for multiplication with one million, while mBtu is mistaken for the SI “m” that denotes division by one thousand. Some companies are using “therm” to describe 100,000 BTU, while other use BtuE6 to avoid any confusions between 10,000 BTU and 1,000,000 BTU.

BTU conversions

Thankfully, there are plenty of online calculators to help us out with converting BTU to watts, watts to BTU, BTU to tons and BTU to kwh. If you want to take the task in your hands, you won’t have any trouble finding the specifications for each measuring unit. For example, one watt is the equivalent of 3.4121 BTU per hour. Likewise, one BTU per hour convers to 0.29307 watts.

BTUs and gas grills

All gas grills available on the market will have a maximum British thermal unit per hour. A gas grill that advertises 35,000 Btu translates to a device that produces that amount of Btu with all its burners in an hour. The gas grill in our example will use approximately two pounds of propane in an hour. However, don’t rely solely on the BTU rating advertised by a gas grill to form an opinion about how much heat it will produce. The rough estimation regards its heat output and only lets you know how much fuel it will consume.

If you’ve been thinking that the BTU number of a gas grill is a clear indicator of its power, you couldn’t be more wrong. Up until now, the ideal gas grill was supposed to produce roughly 100 BTU for every square inch. But now we know we should be paying attention to different factors to guesstimate the efficiency and power of a gas grill. It rarely matters how much fuel a grill will use up. In order to determine the heat output, you should also factor in the design, materials and size of the gas grill.

If the grill is light weight and its overall efficiency is not satisfactory, it will need a higher BTU output to cook food in a reasonable amount of time. However, infrared grills won’t require a large number of BTUs per square inch. Since their build is impressive and the heat from the burners is converted into radiant energy, they are more efficient. Gas grills that boast unrealistic BTUs per square inch are probably hiding a flimsy build.

Calculating BTU per square foot

In order to choose the right heating or cooling systems for a house or a building, you first have to figure out what the required BTU per square foot is. To do this, you will have to calculate the space that needs to be cooled or heated, which will help you in your hunt for the perfect air conditioning or furnace. You can use a BTU calculator or go for the DIY method that we’ll explain step by step below.

The first step implies measuring the square footage in every room within the house that will be heated or cooled. If you have a rectangular room, you will have to measure the length and the width in feet and multiply the two. Triangular rooms call for multiplying the width and the length and then dividing it by two. Circular rooms are a bit trickier, since you first have to determine the radius, which is the line segment from the center of the room to the edge. After that, you can multiply 3.14 by r². Rooms that have odd shapes are even harder to deal with. The simplest way is to split it into smaller sections and take each piece at a time.
If you read the specifications of an air conditioning or furnace, you’ll notice their capacity is determined by BTU per hour. The easiest way to determine the required cooling or heating capacity is to take as a reference 20 BTU per hour for square foot and multiply it by your room’s square footage. However, you should take note that this will not include the insulation your rooms have or the climate.

Air conditioning and BTU

The great majority of air conditioning units on the market express their capacity in BTU. When we’re talking about heating, a ton is the equivalent of 12,000 BTU. The rough estimates that people usually take as guideline are 30 BTU for square foot. To illustrate this, consider that a 2,000 square foot house will need a 5 ton air conditioning unit, which translates to 60,000 BTU. Another factor steps in: the EER stands for energy efficiency rating. This is easily calculated by dividing the BTU of an air conditioning unit to its wattage. To calculate the energy efficiency rating of a 10,000 BTU air conditioning unit that needs 1,200 watts, we divide 10,000 by 1,2000, which gives us the EER, 8.3. Knowing this number and guesstimating how much you will use your air conditioning unit during the summer, you can add up the numbers and see if an AC unit is worth the investment or not.

Image sources: 1, 2, 3.