New heat pump installed...have a couple questions

[kanadian]

Hey guys,

So I ended up getting a Trane XL15i 2 tonne heat pump installed by CR Martin Heating.

Before I get to my question, here is some quick background info:

- square footage of house using forced air is approx 1800 sq ft
- house is about 6-7 years old, not drafty at all
- house faces west so summer sun sets in front of the house where most of the windows are located
- inside temp can get to about 96 degrees after a few hot days
- running heil furnace with 2.5 tonne blower and 75,000 btu
- 10 vents in the house

So after a couple days of warm weather, the outside temp was about 78-79 degrees, inside temp was about 77 degrees. I set my thermostat to cool at 70 degrees. The unit ran for about 2.5 hours and the inside temp had only come down to 75 degrees (from 77 degrees). To me this seemed too slow? Can this unit get my house down to 70 degrees? Could it be too small?

I spoke with the installer and he said it can take up to 5-6 hours of continuous running in this case to get from 77 degrees to 70 degrees however once the that temp is reached it will turn on periodically to maintain. Does this seem correct or is he feeding me bs?

Appreciate your comments guys!

Kanadian

[BaldLoonie]

Air conditioners are great maintainers but can be hard to drop the temp. One thing to consider: you aren't just cooling, you are dehumidifying. So when you have a house open then turn on the cooling, the first things it does is remove moisture. And not just from the air, from all the furnishings, carpet, drapes etc. Could take a while before all the moisture is out and the temp starts dropping. So 2° in 2.5 hours may not be that bad if there was some humidity in the air. Then once the house is cool, isn't near as hard to keep it cool.

Did you tell the dealer to size to keeping the house 70? The industry standard is 75 inside on the hottest day of the air.

[kanadian]

Thanks for the reply BaldLoonie. The part about dehumidifying the house does make alot of sense. What percentage of humidity in the home should be considered low, normal and/or high?

I did tell the dealer I want to be ABLE to bring it down to 70 degrees (maybe not on the hottest couple of days of the year but for the most part). Keyword in the last sentence is "able", in reality I have it set to begin cooling at 75 degrees.

kanadian.