Heat Pump Opinions

[moey]

My opinion is that running a variable speed blower is doing nothing more then compensating for a system that was oversized. Its a delicate balance because often the heating load is more then the cooling load. So when summer rolls around your left with humidity problems you try and solve by running a blower all the time. People expect their air conditioners to respond immediately when the thermostat has not budged in three hours they think its broke. Put in to big of system and your faced with a battle of trying to control humidity levels by modulating a blower with the compressor cycling all the time. That is a advantage of a multi stage system your A/C can run on the first stage only and control humidity using one stage only.

HVAC installers put in huge systems because they dont want callbacks. Before our heat pump was installed our window A/Cs amounted to about 12000btu for 2000 sq/ft. They could keep up on a 90F day it was very comfortable in the house. Now we have about 2 tons stage 1 ( 24000 btu ) its not as comfortable ( much quieter though ). Unfortunately a smaller system would not have worked as well in the summer. Every company that came out tried to sell me a larger system. I finally found one that said Id be more comfortable with a smaller system but would pay a little more to operate.

Make sure whomever came out did a detailed heat loss calculation on your house. If they did not show them the door. Its not ok to size based on what was in your house previously.

 

[timfromohio]

They did do the heat loss survey. The only other evidence I can offer up that the variable speed blower is legit is that local utility providers offer incentives for system upgrades. There are two requirements: heat pump above either 15 or 16 seer (can't remember which) and must have variable speed blower for energy savings. It's either a massive conspiracy or there is some truth to it. I have to believe the latter.

 

[moey]

There may be some units that have a humidity configuration to remove humidity without blasting ice cold air everywhere. Some of the ground source heat pumps did. Although they were the much more expensive units.

I apologize if I tried to sound like a expert Im not I was trying to express my experiences. Its easy to spend someone elses money on the internet.

 

[timfromohio]

There may be some units that have a humidity configuration to remove humidity without blasting ice cold air everywhere. Some of the ground source heat pumps did. Although they were the much more expensive units.

I apologize if I tried to sound like a expert Im not I was trying to express my experiences. Its easy to spend someone elses money on the internet.

No problems! I'm by no means an expert either - just to try get multiple opinions and read as much as possible when having to spend this kind of money.

As an aside, if I were to ever build a house I'd strongly consider not having a single central AC/heating system. I'd rather cool selected areas of a house rather than the entire thing. Put a window AC in the bedroom, maybe one in a family room, done. I have to believe that this would be a cheaper solution over time.

This philosophy might also be used to justify more stoves ....

 

[Highbeam]

Ah, I think I see now. The compressor will sit there in high stage and make a specific amount of btu and the blower will vary its speed as needed to strip 100% of that energy. If at the lowest blower speed and still stripping too much energy, the compressor must be making too much btu so then the compressor will kick down to stage one and the blower will adjust accordingly always acting to wipe 100% of the energy being produced.

 

[fbelec]

the heat pumps i've wired have been 2 stage compressor and 2 stage blower. the unit was controlled by a nest thermostat. it usually started up on low and if it was running a certain amount of time and the temp not coming to set point fast enough then both would kick up to high speed. the brain of the pair was in the compressor. 8 wire thermostat so the unit could talk back and forth to each other. the very last one i did last winter was a york 2 stage compressor variable blower duel fuel if the heat pump could not keep up it switched to nat gas or when the compressor needed to defrost it would kick over to nat gas. the nat gas side was modulating also so it used what it needed for heat and no more.