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.
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.
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.