BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 1:20 p.m.

Our house here in WV currently has normal non-inverter heat pumps and oil furnaces for heat. The problem with the oil furnaces is that both are giving off Monty Python parrot vibes - we've been limping them along for the last four years, but they're pretty much done for.

As GRM knows everything - the options we have is to either replace the existing oil furnaces and hopefully don't need to touch the heat pumps ("hopefully" because the person who installed it didn't do a very stellar job in hindsight with some of the other work they did for us) or rip out the existing furnaces and heat pumps, and replace them with inverter heat pumps with resistive backup heat.

The difference between the two options is basically a nice NA Miata. I can likely make either version work financially, although cheaper tends to be easier. *If* I had a better handle on the real long term viability of us staying here, I'd go inverter heat pump if we think we'd be here another decade. Unfortunately that crystal ball is out of service...

The old oil furnaces cost a bomb to run - I think I spent around $3k on average annually on heating oil, and that's with heat pumps that go down to about 35F. If the running costs of the inverter heat pumps isn't too far off what the current heat pumps seem to cost us, that would mean we'd have the price difference back in our pockets in about 4-5 years.

Note the use of plural - the house has one system for each floor, so we have/need two of everything.

Thoughts? Opinions?

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
9/26/23 1:25 p.m.

Maybe the new heat pumps could pay off in home resale value as well?

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 1:29 p.m.

In reply to GameboyRMH :

Good point, didn't consider that. It might, and if it's not affecting the value itself, it might help with selling it.

chaparral
chaparral SuperDork
9/26/23 2:43 p.m.

You can install Mitsubishi minisplits yourself, despite what the first sentence in the Mitsubishi installation manual says. 

Toyman!
Toyman! GRM+ Memberand MegaDork
9/26/23 3:28 p.m.

I don't know if inverters are the magic answer, but you might do some research on Cold Climate Heat Pumps. I know Gree has several units that will provide heat down to -20 or so. Dakin is advertising units capable down to -4. 

 

WonkoTheSane
WonkoTheSane GRM+ Memberand UltraDork
9/26/23 3:33 p.m.

Another option is to dual-zone a single unit.  I'm not sure what your layout is or what the logistics of that would look like, but I can't imagine it makes sense to run two separate furnaces?

preach
preach GRM+ Memberand UltraDork
9/26/23 4:51 p.m.
Toyman! said:

I don't know if inverters are the magic answer, but you might do some research on Cold Climate Heat Pumps. I know Gree has several units that will provide heat down to -20 or so. Dakin is advertising units capable down to -4. 

 

Up here in NH there is a stipulation in some law that says a heat pump cannot be a rental's sole source of heat. Slightly out of context to the OPs situation, more a reminder to look into code etc. before spending the $$$ for something that hurts value/sale of a house.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 5:27 p.m.
preach said:
Toyman! said:

I don't know if inverters are the magic answer, but you might do some research on Cold Climate Heat Pumps. I know Gree has several units that will provide heat down to -20 or so. Dakin is advertising units capable down to -4. 

 

Up here in NH there is a stipulation in some law that says a heat pump cannot be a rental's sole source of heat. Slightly out of context to the OPs situation, more a reminder to look into code etc. before spending the $$$ for something that hurts value/sale of a house.

It's the same here - you have to have backup heat if you've got heat pumps. In this case, that would be the aforementioned resistive heat that would be fitted in addition to the heat pumps and hopefully hardly ever turn on. Our local HVAC company already warned me about that and it's included in their installation quote.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 5:30 p.m.
WonkoTheSane said:

Another option is to dual-zone a single unit.  I'm not sure what your layout is or what the logistics of that would look like, but I can't imagine it makes sense to run two separate furnaces?

Making sense or not, that's the original layout. One furnace and a/c setup to heat the basement and main floor, a second one to deal with the top floor. Not sure why they set it up like this 20 years ago, but that's basically the setup we're stuck with, at least without major reconfiguration.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 5:32 p.m.
Toyman! said:

I don't know if inverters are the magic answer, but you might do some research on Cold Climate Heat Pumps. I know Gree has several units that will provide heat down to -20 or so. Dakin is advertising units capable down to -4. 

If I understand correctly, those are basically inverter heat pumps. I think the ones we were quoted on are supposed to be good down to -20F, although the HVAC contractor mentioned that the ones he's installed seem to all want backup when it gets that cold. The -4F might be more realistic.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/26/23 5:33 p.m.
chaparral said:

You can install Mitsubishi minisplits yourself, despite what the first sentence in the Mitsubishi installation manual says. 

This is for a house with about 3500 sq ft of living space, to replace and existing HVAC system. I don't think that's what mini splits are designed for, although I might be mistaken.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
9/29/23 4:01 p.m.

Looks like this question might have been moot in a sense as the high efficiency units our HVAC guy would like to use are on back order for at least two months, potentially longer.

Guess I get to figure out if we risk trying to limp the existing oil furnaces along for at least part of the winter or replace them like for like and spend the difference on a four post lift for the shop.

chaparral
chaparral SuperDork
10/26/23 2:00 p.m.

In reply to BoxheadTim :

It is. In Michigan I would be looking at 2 one-ton single-head systems for that space and 2-3 half-ton units for the bedrooms. You need less hardware than you think; heat transfers well across a living area and through interior walls. 

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