Someone recommend a forced air gas furnace.

[NoTine42]

http://precisioncomfort.com/2016/01/myth-heat-pumps-are-not-efficient-in-cold-weather/

That 32F setting was the lowest temp the install tech would allow for that heat pump. I think he normally set it at 40F.

The most annoying thing about that heat pump was the occasional “defrost” cycle..basically running in A/C direction to defrost the outdoor unit.

 

[BoomerD]

Mine runs down into single digits.

 

[skull]

This does not address the maintenance issue, but the useful life seems comparable:

http://culluminc.com/wp-content/uploads/2013/02/ASHRAE_Chart_HVAC_Life_Expectancy 1.pdf

My HVAC knowledge is limited to say the least. Really would like to know.

I don't see mini splits on there. The Mitsubishis are nice and the inverter units are bad ass. Especially the VRF systems those things are really cool. In big buildings they can have hundreds and hundreds of the indoor units. If one rooms hot and ones cold they work like a heat pump and put the heat from hot room into the cold room. Super efficient.

The regular Mitsubishi inverter units with hyper heat that can do 4 heads are really cool and extremely efficient. I've only put one in and breathed a sigh of relief when my labor warranty was up. They arn't really meant to be worked on, you can't even adjust the refrigerant level with out pulling the charge and weighing it in. The electronics are about impossible for a regular hvac guy to troubleshoot. Even the factory trained guys have trouble, they just arn't meant to be field repaired.

The Mitsubishis are pretty reliable, other brands not so much. Problem with the Mitsubishi is if it does break early on you might be starting all over.

 

[skull]

That 32F setting was the lowest temp the install tech would allow for that heat pump. I think he normally set it at 40F.

The most annoying thing about that heat pump was the occasional “defrost” cycle..basically running in A/C direction to defrost the outdoor unit.

Hes an idiot modern heat pumps are still more efficient than electric strip heat down to about 5F.

 

[skull]

I was just checking my MIL’s thermostat and was explaining that plain “Heat” is good as it uses the heat pump (until the outdoor temp sensor drops below 32F). You dont want to use “e.Heat” because it only uses gas....

Now wait!!! I have always known e heat as Emergency Heat (gas only), but hearing it out of my mouth, why does e.heat mean gas? I sound like an idiot explaining that e Heat is gas.

Selecting “E. Heat” on a thermostat to use gas-only mode is a major UI fail.

Almost as amusing as pressing Start to shut down.

Emergency heat is just your auxiliary heat. Can be whatever you have electric/gas/oil. It just locks out the heat pump and only runs the back up heat. If you have natural gas 25f 30f degrees isn't a bad switchover point. If its electric back-up run that heat pump down to 0F- 5F. You can look up your model heat pump and find the coeffcient or whatever its called at different temps. If I remember right anything over 1.7 its better to keep the heat pump running.

 

[gill77]

I don't see mini splits on there. The Mitsubishis are nice and the inverter units are bad ass. Especially the VRF systems those things are really cool. In big buildings they can have hundreds and hundreds of the indoor units. If one rooms hot and ones cold they work like a heat pump and put the heat from hot room into the cold room. Super efficient.

The regular Mitsubishi inverter units with hyper heat that can do 4 heads are really cool and extremely efficient. I've only put one in and breathed a sigh of relief when my labor warranty was up. They arn't really meant to be worked on, you can't even adjust the refrigerant level with out pulling the charge and weighing it in. The electronics are about impossible for a regular hvac guy to troubleshoot. Even the factory trained guys have trouble, they just arn't meant to be field repaired.

The Mitsubishis are pretty reliable, other brands not so much. Problem with the Mitsubishi is if it does break early on you might be starting all over.

Thanks. The Mitsubishi is what I did not choose. Sounds insanely efficient. My beef is that currently if any zone kicks on, I get the noise from the furnace just a few feet from me.

Also learned that we have perhaps the highest gas prices in the country. Go figure.

 

[skull]

Thanks. The Mitsubishi is what I did not choose. Sounds insanely efficient. My beef is that currently if any zone kicks on, I get the noise from the furnace just a few feet from me.

Also learned that we have perhaps the highest gas prices in the country. Go figure.

Sounds like they over sized the furnace/ the duct work is undersized or its just the zoning setup. I don't like zoning regular systems for a number of reasons noise is one of them.

 

[gill77]

Sounds like they over sized the furnace/ the duct work is undersized or its just the zoning setup. I don't like zoning regular systems for a number of reasons noise is one of them.

I think you called that right. Pretty sure the duct work is undersized. Remodels are hell.

 

[Kaido]

No you don't mini-splits are expensive and disposable. Most techs arn't trained to repair them and even the ones that are have trouble fixing them.

My buddy did Mr. Slim H2i's from Mitsubishi. Crazy money (like $2k installed/ea), but iirc they can pull heat down to -13F, unlike most other mini splits. Plus he's in a multi-generation home, so everyone gets their own temp controller, which is pretty nice.

 

[skull]

I think you called that right. Pretty sure the duct work is undersized. Remodels are hell.

Yeah most likely guys don't know how to size it right for one. If they even use a ductulator they go off .1 no matter what total effective length they have. Then with the open floor plans everyone wants theres no where to cram it anyway. I'm doing the electric on a 5000sqft gut. Owners decided to use an electric spacepak on the 2nd and 3rd floors when theres gas available. Just so they wouldn't lose like 8 sq ft on the 3rd floor. Costing them way and more and the future owners way more in electric. If I was the hvac guy on that one I probably would've refused for the sheer stupidity.

 

[Red Squirrel]

My ducts are probably slightly undersized too, when I look at them they just seem so small, and I find I don't have good airflow on the lower floor. One of these days I should redo it. Really I just need to redo that one trunk as the higher floor one is ok given heat rises and fact that some of the vents are also dedicated runs straight from the main plenum.

Eventually I want to setup automated dampers and a return bypass damper so I can fine tune air flow and have different programs such as if I want upstairs to be warmer it would close upstairs vents etc. It would also need to monitor air flow, plenum temp and other parameters and let air through some of the closed vents as required.