Home Cooling and Saving Energy

Home Cooling and Saving Energy

From Ken:

I'm getting ready to buy a house in the next 2-3 months. I understand that the roofing expenses for a 3000 sq ft home will be more for a single story home than a multi-story home of the same sq footage.

But I will be looking for a house in Texas, and I was thing that a single story house may be less expensive to cool than a multi-story house. I'm renting a 2-story home now and the second story is always hot, not matter how cold the first story is. So, I really have to crank the A/C to make the upstairs remotely comfortable, as I work from home with an upstairs office.

Am I right in thinking that a single story home would be less expensive to cool, everything else being equal?

Hi Ken

I always suggest discussing questions like this with your local energy (electric) company. They always have very accurate info.

But here is what I have learned over the years, building in both the south and in the north.

The reason you have to “crank” the A/C is that the system in your rental house is not balanced.

To balance a Heating/AC system in a 2 story house, dampers are put in the air supply plenums which are controlled either manually, electronically, or by temperature.

The plenum to the 2nd floor will restrict  air flow to the 2nd floor during the heating phase as less air flow is needed to heat the 2nd floor (heat rises by itself).

The plenum damper in the lower level (1st floor) will restrict air flow to the lower level during the A/C phase, forcing more air upstairs where it’s needed (cold air falls).

Dampers can also be put in the individual duct work system that runs to each room to restrict air flow in some ducts, forcing more air to flow other ducts, or you can simply adjust the individual registers in each room to restrict air or not restrict air to achieve the same result.

This is the way it was done back in the early days when central A/C was a relatively new luxury.

It is horribly inefficient and a pain in the neck if you had to run around closing or opening dampers by hand.

Newer well built homes with modern energy efficient A/C systems use separate systems for different areas, called zones, to perfectly balance comfort and efficiency.

Two systems should have been installed in your rental house.

Two smaller A/C systems, one down & one up would have cost very little more to install than the one larger system that is plagued with the problems you are experiencing, and would use a hell of a lot less energy to operate.

I think you'll find that the cost savings of building a 2 story 3,000 sq. ft. home will more than offset the cost of adding a separately zoned, well insulated upstairs central cooling system, which is what any 2 story home SHOULD have, even in Northern climates.

Even a one level 3,000 sq. ft. house should have 2 separately zoned systems for heat and/or cooling. That's too large an area for one system to maintain equal comfort throughout.

Carl