Ventilate or apply more insulation to roof containing furnace and AC?
We have a 2 story Cape with a single air handler running off a heat pump, (down to 35) & a condensing furnace (For colder days). The heat pump is also our AC unit.
The bulk of the units are in the attic with only the heat pump/ac condenser out side.
We have a roof and wall sealed and unvented attic. There is no insulation under the floorboards.
We are finding ourselves having to run portable air conditioners this winter as the heat transfer coming down from the attic is enormous.Even with the upstairs side of the system set to “off” beget heat significantly higher that what is being called for on FLOOR ONE.Wondering if we should be investing in floor insulation for the attic too?
We also would like to know if there are better dampers I can find to close of the airflow to one floor or the other?
Thanks for any suggestions.
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If you have HVAC equipment (and ducts too, I assume) in an unconditioned attic that is currently uninsulated, you have two options to improve the situation: turn the attic into conditioned space by insulating at the roofline, or build an insulated room for the HVAC equipment inside the attic, and then air-seal and insulate the attic floor. The costs of each are bound to be heavily dependent on site-specific factors such as the complexity of the roof, the amount of time before you need to re-roof, the location of the HVAC equipment, the location and condition of the ducts, etc.
It's not clear to me whether or not your attic is insulated at the roof and gable walls, at the attic floor, or not at all. Also not clear where the overheating is occurring, but I'm assuming the upstairs is too hot and that's where the portable A/C units are. Also, what climate zone are you in?
Sounds to me like you need an energy auditor to evaluate the entire situation and make recommendations. If your attic gets so hot in winter that it overheats the second floor, what does it do in the summer?
Thom,
I agree with the other commenters; we need to know what type of insulation you have on your roof or ceiling; where the insulation is located; and the estimated R-value of the insulation.
It sounds like your house could have many problems -- especially since you are experiencing wide temperature differences from room to room. Among the possible problems:
1. You house is very leaky (in other words, it has air leaks).
2. Your house is poorly insulated.
3. Your heating system is poorly designed (with a poorly designed duct system).
4. Your ducts are leaky.
Ideally, you would hire an experienced home performance contractor familiar with "house as a system" thinking who could help you.