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What Size AC Does My House Need ?
HVAC & Energy Library - Residential Information

What size air conditioner do I need for my house? 

One Ton of cooling equals 12,000 BTU’s (British Thermal Units), which incidentially is the heat required to raise one pound of water by one degree F.

The correct BTU value (or tonnage) you need for your house  is an engineered value unique to your home. It involves heat gain values (in BTU’s that enter the house thru walls, doors and windows. The higher the insulation or ‘R’ value in these area, the lower BTU air conditioner you will need. It also takes in the solar load. Obviously, a house with a lot of south facing glass is going to require more air conditioning than one with little or shaded south facing glass. Finally, ventilation and infiltration of air are factors. Is the house built to currrent standards and is tight, or is it an old original farm house where a 10 MPH wind outside relates to a 5 MPH wind inside? Hot humid air entering the house puts additional load on the air conditioner.

Central air conditioning comes in some standard sizes: 1.5 latest celebrity news Ton, 2 Ton, 2.5 Ton, 3 Ton, 4 Ton, & 5 Ton, so depending on the result of a heat gain study, you will not likely an get an air conditioner to match the results and will have the select the one that most closely matches your results.

One problem that faces our industry is over sizing air conditioning. The thought is if 2 Ton will do the job, lets put a 3 Ton unit in and it should do it better. Wrong, the problem with oversizing is that the air conditioner only dehumidifys while it is running (as seen by the condensate water running out of the drain from the indoor portion of your air conditioner. If the air conditioner is oversized it will cool the house down quicker but then will shut off. The temperature will be right but the humidity may still be too high and you will still feel uncomfortable. You may have to lower the temperature even further in order to remove the humidity. If your air conditioner needs to run steady during a heat wave, perfect. Your house will be dry and even at 76 degrees F, you will feel comfortable.

Not every customer is willing to go to the expense of a heat gain study, so many contractors will, thru experience, Gay Porn estimate the required tonnage. Realistically, we can get pretty close to the required tonnage this way, but unless the job is engineered for cooling, there is no guarantee. Many will use a rule of thumb: 1000 sq. ft. per ton of cooling, and make adjustments to this value if the house has any unusual considerations.

 Tom McDonald your social media marketing partner

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