Mini split heat pump????????

[joeysmith]

The house is a 2 BR 1100 sq ft single story attached to a 2000 sq ft shop that has it's own heat and A/C. Side walls are R 36+ and one of the longer walls is adjacent to the shop so heat/cool loads are small.

My thoughts regarding mini split (single head) were to leave the original system in place and if something failed I could fall back on the mini split for heat and A/C using the blower on the existing system wired up for low blower speed.

In that scenario I would recommend a single zone mini split in the master bedroom


You gain the ability to keep that room cooler or warmer depending on the season/your comfort an have a little redundancy if one of the systems breaks down.

We have done exactly that many times an the homeowners love being able to keep the master bedroom cooler (usually) than the rest of the home

 

[joeysmith]

Some things to consider do you feel you need a head unit in every room? How big is your house? Is it one story? Are you looking at one multizone or two?

My 2 story has 2 24K outside units with 5 head units. Old, large shotgun house. Downstairs is all open with 2 1200K heads, one front and back. Upstairs has 4 BR and 2 bath. Master BR is huge with 1800K head , 2 BR each have 9000 head and one seldom used BR has none. Because of it's location it would have required it's own outside unit on a porch I didn't want to look at it anyway. It's probably under spec'd for the house but I did that on purpose. Equipment cost less and It is very comfortable and economical for us. But we don't require it to be cold or toasty just comfortable. Wife keeps them at set 79 degrees we have ceiling fans in every room.

Country house has big rooms and tall ceilings lots of original leaky windows. It does have 9-12 inches of insulation in the attic. It has ceiling fans in every room. It has 2 24K outside units with 6 head units. 12K heads in kitchen, entry-dining and big living room. 9K heads in 3 BRs. None in bathrooms. I had to put one of the outside units where I didn't want to look at it, but I'm used to it now. One of the BRs I had to run a long line under the house to reach. This system is also a little undersized. We leave it off when not there and it cools down and stays comfortable quickly.

My houses never had any AC and I really like the mini splits. That doesn't mean they have been without some issues and some learning how to keep them clean.
I would guess since you already have a central system replacing it with a modern central system by a good installer would be a lot cheaper and work better than what you had.

These are the kinds of homes we recommend them for

Any time it would be a major remodel to run ductwork minis are a very handy option

 

[MM-TX]

The house is a 2 BR 1100 sq ft single story attached to a 2000 sq ft shop that has it's own heat and A/C. Side walls are R 36+ and one of the longer walls is adjacent to the shop so heat/cool loads are small.

My thoughts regarding mini split (single head) were to leave the original system in place and if something failed I could fall back on the mini split for heat and A/C using the blower on the existing system wired up for low blower speed.

I think that would work well. My 2 story I left the gas furnace that has duct to down stairs and use it on coldest days when the heat pumps struggle. Glad I have it.

 

[da.bees]

The house is a 2 BR 1100 sq ft single story attached to a 2000 sq ft shop that has it's own heat and A/C. Side walls are R 36+ and one of the longer walls is adjacent to the shop so heat/cool loads are small.

My thoughts regarding mini split (single head) were to leave the original system in place and if something failed I could fall back on the mini split for heat and A/C using the blower on the existing system wired up for low blower speed.

This might be ok but I'd test it first in case ducts need attention. Close or cover outflow vents, turn blower on and introduce smoke at intake. Look for leaks in ducts. Second test. Preferably on a hot day with any type attic vent fan off and hvac vents in normal,open, turn blower on. Use an accurate thermometer to find INTAKE temperature then find temperature at all outflows. Unless ducts are well insulated, air will pick up heat as it flows through ducts. There's diy duct insulation kits available to overlay old insulation with additional.

I 100% agree with a back-up unit. In most homes (especially where there's only 1 or 2 people) central system can be turned up or off while a m-split cools den during day. That can save enough energy cost to pay for m-split and be there in case central goes down.

 

[da.bees]

These are the kinds of homes we recommend them for

Any time it would be a major remodel to run ductwork minis are a very handy option

I can't recall name of builder but a tract home builder in the 50s-60s put air handler in a hall closet, fur-downed ceiling in hall with supply vents through wall and transoms. A company called First Co. manufactures a ceiling mounted handler that caters to multi-family. This would be a viable solution for many situations and the average diyer.

 

[joeysmith]

I can't recall name of builder but a tract home builder in the 50s-60s put air handler in a hall closet, fur-downed ceiling in hall with supply vents through wall and transoms. A company called First Co. manufactures a ceiling mounted handler that caters to multi-family. This would be a viable solution for many situations and the average diyer.

Yes but a lot more demo an construction than putting minis in

 

[da.bees]

Heat pumps are progressively doing better at lower temperatures but if one has an older unit that fades, here's a simple solution where back-up is resistant. Most handlers have room to add additional heat strips. Add a low wattage strip and connect to t-stat wire for heat pump. Interrupt this wire with a toggle switch for periods of moderate weather. In the case of elderly parents or such, the aux heat strip wire can be interrupted with outdoor temperature sensor.

 

[Dusty MI]

I used to service fuel-oil furnaces back they were used a lot in the country side, and have installed a few new ones. I still have some pieces of duct if anyone is interested.
I still have the equipment and tools to make sheet metal duct, and electric pull boxes.
Dusty

 

[joeysmith]

Heat pumps are progressively doing better at lower temperatures but if one has an older unit that fades, here's a simple solution where back-up is resistant. Most handlers have room to add additional heat strips. Add a low wattage strip and connect to t-stat wire for heat pump. Interrupt this wire with a toggle switch for periods of moderate weather. In the case of elderly parents or such, the aux heat strip wire can be interrupted with outdoor temperature sensor.

Never seen a high wall mini unit that you could add heat strips to

My climate the issue isn't heating below a certain temperature with the minis
Most will do fine with that.

We have high humidity on the cold weather a lot

This causes the outdoor unit to need to defrost a lot more than other climates so they can get behind pretty

 

[da.bees]

Yes but a lot more demo an construction than putting minis in

Nothing is etched in stone friend, it's an option. Case in point, far more homeowners posse tools and experience for carpentry than duct fabrication. Professional duct and vent techs' arms and hands look like they've fought with a bobcat, the average Joe could easily slit his wrist or throat. Then there's the matter of heat stroke. If the 65 year old handyman doesn't bleed himself out, he might croak from attic heat. Options, always nice having options in shirt pocket and they don't cost a dime.