Which Heating/Cooling Options on 2-Room Attic.
Well, thanks for everyone’s input on suggestions/ideas on heating and cooling our newly renovated attic.
It has come down to the following.
Whirlpool Heat Pump with electric heat strip or a Fujitsu 2-zone ductless-mini split. The difference between the 2 is only $.
We do live in Boston, so the temp outside does get very cold on some days. I am just trying to see which one will be more efficient and save on electric based on our winters?
Also, which one would be more reliable, and less costly to maintain/repair.
Thanks for your input.
Last edited by beenthere; 09-27-2009 at 10:00 AM.
Reason: Removed price
We just did one, used a 1 ton Coleman outdoor unit and a 5 kw air handler in the kneewall. Same thing I did for a friend living above her daughter's garage. Only problem is these 1 ton units are getting pretty scarce. If your space is bigger then the common 1.5 ton may be more appropriate. These 2 spaces we did were small & tight enough that 1.5 ton would be wrong.
Boston's climate is too cold to use a heat pump as a sole heat source. If you go with the Fujitsu, you'll need a baseboard heater (or some other supplemental heat source) on a separate thermostat for use when when temperatures drop below the Fujitsu HP's balance point and lower operating temperature. Your Whirlpool bid includes backup heat--you won't need baseboard heaters.
Thank you all for your replies...
I have been leaning towards the 2 ton Whirpool Heat Pump with the electric strip for backup heat. However, my HVAC guy is telling me that we need to run additional wires to accomidate the heat pump and electrical strip....making my electrical costs higher...thats when we started thinking about the ductless system.
You'll need new wiring runs no matter which option you chose.
Has anyone done a load calculation for the attic? It's imperative that anything you have installed be sized appropriately to the heat gain/heat loss loads in the space. Two tons may well be oversized for cooling a two room attic.
If you install an oversized ducted heat pump, you'll get good heating performance--and low heating costs--but humidity removal in cooling season will be poor. If Boston gets humid summers and you want to use your attic during the summer months, this will be a big problem.
If maintaining comfort in cooling season is important to you, get the ductless and some baseboard heaters for backup heat. It doesn't matter if you oversize ductless units as they will throttle their output to match loads as necessary.