How to Add Central AC in Old Homes

Older homes have a lot of wonderful features, but one thing they don’t have is central air conditioning. That becomes important in heat of the summer when fans just stir the air and room air conditioning units only seem to taunt you with how cool your home could be. Because of this, many owners of older homes make adding central air conditioning to their homes a high priority. An average home can have a new system added to a forced-air heating system in a couple days at an affordable cost.

Instructions

1. Have your contractor do a heat gain calculation. This is a fairly easy calculation that will show how much your heat gain your home is subject to. Once this is known, the cooling contractor can tell you how large an air conditioning unit your home will need. The size of your air conditioning unit needed will also be affected by where you live, how well insulated your home is, how your home is oriented to the sun and how energy-efficient your doors and windows are.

2. Select the proper size air conditioning unit. Use the heat gain calculation to pick a unit that is capable of cooling your home. A unit that is too small will have trouble cooling your home and cost more to operate on hot days. An oversized unit will cool the house too quickly so that it doesn’t help control humidity. It will also be more costly to run.

3. Find a model with a high SEER rating. SEER is the seasonal energy efficiency rating of an air conditioner. New units must have at least a 13 rating, but if you can find a model that has a higher rating, it means that the unit will be able to remove more BTUs for each watt of power it uses. It will be more efficient and cost less to operate. However, it will also cost more to purchase.

4. Choose a package or split system. Most air conditioning systems are split systems, meaning the condenser is outside and the fan and coil system are inside. A package system has everything in one unit. In selecting a split system, make sure the condenser is not placed near an office or bedroom. All condensers make noise and it could be distracting.

5. Install the ducts. Ducts may need to be added to your home to deliver the air throughout. Ducts can run through closets to move between floors. You will need to have duct registers in every room. You can also tap into furnace ducts since they won’t be used in the summer months.

6. Have existing ducts inspected. This ensures the existing ducts are large enough to handle the volume of air needed to cool a home. An inspection will also tell you if your furnace blower needs to be upsized, if certain ducts can be sealed to increase efficiency and if new registers would increase air flow in certain rooms.

References

• This Old House.com
• House In Progress.net
• Superpages.com