HVAC help/questions

fredridge · Dec 3, 2024

When we bought our house a couple years ago it had radiant ceiling heating and a single cassette 18k btu mini split heat pump in the living room.
the ceiling heating no longer works so we have been making due with the heat pump and a fireplace. The heat pump was installed in 2016 and has some issues and isn't enough to maintain temps when it gets into low 30's and 20's.

So I am looking at options.
Our house is only 1k sqft 3 bedroom and just my wife and I with occasional family visiting for a few days.

I am thinking a newer multi zone mini split, but would also be open to installing a ducted system. I am also interested in those combo systems that use the water heater to store energy for the AC/heat pump.

Anyone have experience with this stuff? Should I be looking at mini split or ducted?
Any thoughts on the Mr Cool DIY stuff?

Is there any easy way to figure out how many BTU's since it needs to take over all heating and cooling?

Anyone have recent experience? In the industry? Do this as a side gig?

Thanks.

Jay Walk · Dec 3, 2024

Wife and I switched from ceiling to ducted heat pump back in 2009, cost then was $10,000. No regrets other than the cold months the heat strips run and cause the electric bill to be as much or higher than the zonal ceiling heat. A/c is awesome though and dirt cheap to run.

Not sure what you mean by water heater storing energy but stay away from the apollo system, those were problematic. I have installed heat pump water heaters for clients but recently have been doing fix it work on a newer condo with a heat pump water heater in the garage and the fan is noisy and annoying throughout the entire first floor (sounds like the furnace is running) you can even hear it on the second floor, furthermore if you run the hot water for even a short period, that water heater fan runs for a long time. I would never install one of those in my own home.

A quick fix for the bad ceiling heat in the living room is to drop some romex down from the wall thermostat and install a cadet wall heater.

CentraloregonJ · Dec 3, 2024

Not in the industry, but upgraded our baseboard electric to a multi zoned mini split at about 1/4 the cost of trying to run ducts in a house on a slab. About 4.5 in equipment, and another 1 to have an actual hvac guy come braze all the lines and charge it up ( 4 zone, 2k sq ft). Winter electricity bills down by 50%, system should pay for itself in savings by spring (4 winters). As far as equipment, I'd pass on the mr cool stuff, if you're budget conscience, the Trane RunTrue (Gree) was what came reccomended to us from a few guys in the industry

fredridge · Dec 3, 2024

Jay Walk said:
Wife and I switched from ceiling to ducted heat pump back in 2009, cost then was $10,000. No regrets other than the cold months the heat strips run and cause the electric bill to be as much or higher than the zonal ceiling heat. A/c is awesome though and dirt cheap to run.

Not sure what you mean by water heater storing energy but stay away from the apollo system, those were problematic. I have installed heat pump water heaters for clients but recently have been doing fix it work on a newer condo with a heat pump water heater in the garage and the fan is noisy and annoying throughout the entire first floor (sounds like the furnace is running) you can even hear it on the second floor, furthermore if you run the hot water for even a short period, that water heater fan runs for a long time. I would never install one of those in my own home.

A quick fix for the bad ceiling heat in the living room is to drop some romex down from the wall thermostat and install a cadet wall heater.

Thanks.
There are companies that make a heat pump system where it uses the water heater to store and release energy. Almost like a thermal system but instead of in ground it's the actual water heater. Read a few articles and seen a segment on This Old House.

I was thinking about using the thermostats as you suggest as I replaced them a couple of times until I figured out we broke the circuit when we installed wired smoke detectors. The wiring is slightly complicated as it's in some kind of series.

We have talked about converting the garage and a small addition so I have been waiting but don't think it's smart to wait anymore.

fredridge · Dec 3, 2024

CentraloregonJ said:
Not in the industry, but upgraded our baseboard electric to a multi zoned mini split at about 1/4 the cost of trying to run ducts in a house on a slab. About 4.5 in equipment, and another 1 to have an actual hvac guy come braze all the lines and charge it up ( 4 zone, 2k sq ft). Winter electricity bills down by 50%, system should pay for itself in savings by spring (4 winters). As far as equipment, I'd pass on the mr cool stuff, if you're budget conscience, the Trane RunTrue (Gree) was what came reccomended to us from a few guys in the industry

Thanks. I would rather spend on something that will last and not have problems, but struggle with writing checks.

We have an attic and a crawl space so it might be easier

ron · Dec 3, 2024

Put a cadet heater with a thermostat in each room. Only heat the room you are in. Go to bed at night and you're only heating the bedroom not the whole house. Years ago there were electricians that were experienced in troubleshooting and repairing ceiling heat. I don't know if any of them still exist. Probably not too many people are still using ceiling heat

fredridge · Dec 3, 2024

ron said:
Put a cadet heater with a thermostat in each room. Only heat the room you are in. Go to bed at night and you're only heating the bedroom not the whole house. Years ago there were electricians that were experienced in troubleshooting and repairing ceiling heat. I don't know if any of them still exist. Probably not too many people are still using ceiling heat

I am pretty sure the problem is where we cut through to install wired smoke detectors.

It's a small house and our spare bedrooms are our offices so we are in and out of them all the time so other than when we have guests overnight it's all pretty much the same.

fredridge · Dec 3, 2024

Made a video appt with these guys for info

Harvest Smart Thermal Battery. The Smartest HVAC on Earth

Heat your home, not your home planet. Reduce carbon emissions from home heating up to 90% compared to gas furnaces and save up to 40% on home energy costs.

www.harvest-thermal.com

doninoregon · Dec 3, 2024

Ducted is a lot more expensive to install vs minisplits especially as a retrofit but that depends on the number of rooms.

A rough rule of thumb for heating load is 30 to 50 btu's per sq ft of living space, depending on insulation efficiency.

MikeInOr · Dec 3, 2024

I have installed a few mini-spits. The first one was a Fujitsu 9000btu in my great room. I installed everything including the electrical then called the HVAC companies to do the flared fittings and line prep. Only one of the companies would talk to me and they charged $900 (several years ago) to do 4 flares and the vacuum down. The guy had never heard of Nylog and didn't have a Nitrogen tank to pressure test with.

My second install was a Mitsubishi 3 zone for my 3 bedrooms (2 x 6000btu + 1 x 9000btu). I purchased a vacuum pump, yellow jacket gauges, a Yellow Jacket eccentric flaring tool, a nitrogen tank, and a couple of fittings. I did the whole job myself including the electrical. The only problem I have encountered is during the spring when it is cold in the down stairs bedrooms and hot in my upstairs bedroom. All the head units will heat or all the head units will cool. You can't heat with some head units while also cooling with the other head units at the same time with the Mitsubishi mini-split system I purchased. We deal with this.

I then helped a friend install a 1 zone Mitsubishi mini-split in this office at his house. That was an easy install since I had a good bit of experience.

Last spring my Fujitsu started throwing an error code after 12 years of no issues. After tons of Googling I narrowed down the problem to low on coolant. I bought a tank of R410a (which is no longer made and getting expensive) and a refrigerant scale. I added 6oz of R410a and it has been working perfectly since.

The Mr. Cool units come with pre-charged lines so you don't need all the tools, vacuum pump, nitrogen, etc. The down side is you have to buy the correct length pre-charged lines and it is more difficult to measure the proper length than it seems like it should be. It is best to order a little bit long and have a small coil at the central unit. Since I did all of mine without pre-charged lines I was able to cut them all to a perfect length.

Fujitsu and Mr. Cool have good reputations. The Mitsubishi mini-splits are the top of the line and definitely worth their little higher price IMHO! HVAC companies seem to want to sell the cheapest min-splits available so they can make the biggest markup. My friends Mitsubishi mini-split cost about $2400. The best quote from an HVAC company was near $8000 for a no-name mini-spit.

I do have a central heat pump with duct work and it was crap. No room was ever warm or cool because of the lousy duct work install. I love the mini-splits as does everyone else in the house. Everyone has a comfortable temperature in their room and the electric bill is a LOT lower than running the central heat pump!

First question should be can you do the electrical work yourself safely?

P.S. No HVAC tech I have ever met knows how to properly size a mini-split. They all pretty much shoot from the hip.

fredridge · Dec 3, 2024

MikeInOr said:
I have installed a few mini-spits. The first one was a Fujitsu 9000btu in my great room. I installed everything including the electrical then called the HVAC companies to do the flared fittings and line prep. Only one of the companies would talk to me and they charged $900 (several years ago) to do 4 flares and the vacuum down. The guy had never heard of Nylog and didn't have a Nitrogen tank to pressure test with.

My second install was a Mitsubishi 3 zone for my 3 bedrooms (2 x 6000btu + 1 x 9000btu). I purchased a vacuum pump, yellow jacket gauges, a Yellow Jacket eccentric flaring tool, a nitrogen tank, and a couple of fittings. I did the whole job myself including the electrical. The only problem I have encountered is during the spring when it is cold in the down stairs bedrooms and hot in my upstairs bedroom. All the head units will heat or all the head units will cool. You can't heat with some head units while also cooling with the other head units at the same time with the Mitsubishi mini-split system I purchased. We deal with this.

I then helped a friend install a 1 zone Mitsubishi mini-split in this office at his house. That was an easy install since I had a good bit of experience.

Last spring my Fujitsu started throwing an error code after 12 years of no issues. After tons of Googling I narrowed down the problem to low on coolant. I bought a tank of R410a (which is no longer made and getting expensive) and a refrigerant scale. I added 6oz of R410a and it has been working perfectly since.

The Mr. Cool units come with pre-charged lines so you don't need all the tools, vacuum pump, nitrogen, etc. The down side is you have to buy the correct length pre-charged lines and it is more difficult to measure the proper length than it seems like it should be. It is best to order a little bit long and have a small coil at the central unit. Since I did all of mine without pre-charged lines I was able to cut them all to a perfect length.

Fujitsu and Mr. Cool have good reputations. The Mitsubishi mini-splits are the top of the line and definitely worth their little higher price IMHO!

I do have a central heat pump with duct work and it was crap. No room was ever warm or cool because of the lousy duct work install. I love the mini-splits as does everyone else in the house. Everyone has a comfortable temperature in their room and the electric bill is a LOT lower than running the central heat pump!

First question should be can you do the electrical work yourself safely?

Thanks good info.
The current unit already has a 30 or 35 amp 220v which with current efficiency should allow me a 4 split 2.5 to 3 ton.
My panel will have no problem if I need to upgrade that since I will be ditching the ceiling stuff.

I am unsure about my handyman skills for this level but may have some friends/family who can help.

Sounds like the mini split is the way to go and my wife said she would prefer more control.

I got an estimate a couple years ago and it was like 10k for same size unit but newer. Seemed pretty insane to me. So I'm looking at options, even seen some used ones on Craigslist. Just trying to make the best decisions.

I know with traditional systems you have to size them just right or the freeze over, but it seems like that is not an issue with the minis split. Is that accurate?

fredridge · Dec 3, 2024

One other issue is needing it to be appropriate if we ever go to sell. Like what if every room doesn't have a cassette.

MikeInOr · Dec 3, 2024

fredridge said:
Thanks good info.
The current unit already has a 30 or 35 amp 220v which with current efficiency should allow me a 4 split 2.5 to 3 ton.
My panel will have no problem if I need to upgrade that since I will be ditching the ceiling stuff.

I am unsure about my handyman skills for this level but may have some friends/family who can help.

Sounds like the mini split is the way to go and my wife said she would prefer more control.

I got an estimate a couple years ago and it was like 10k for same size unit but newer. Seemed pretty insane to me. So I'm looking at options, even seen some used ones on Craigslist. Just trying to make the best decisions.

I know with traditional systems you have to size them just right or the freeze over, but it seems like that is not an issue with the minis split. Is that accurate?

The Mitsubishi I installed with 2x 6000btu and 1x9000btu runs on a 24000btu (2.4 ton) compressor. A heat pump does not put out hot air like electric resistance heat instead it puts out warm air. We keep the head units running 24 hours a day and they run at a VERY slow rpm on the compressor and the head unit blowers. It might seem counter intuitive but it is very efficient this way. Instead of ramping up for a heavy load and constant power cycling like central HVAC it is a constant low load.

The better you size the mini-splits to the actual need the more efficient they are.

Both the Mitsubishi and Fujitsu will detect if the compressor coils freeze up and run the compressor backwards to melt the ice off the coils. I have never had a problem with the inside head units or compressor needing attention due to freezing up. My Mitsubishi and Fujitsu are both rated to work at a lower outdoor temperature than the cheap brands. Here in Central Oregon it will hit -5F or even -10F outside and they still run and put out warm-ish air but we fire up the woodstove or electric space heaters to augment the mini-splits when it gets this cold. Not even all of the Mitsubishi and Fujitsu mini-split models are rated for sub zero outside temps. I was aware of this and made sure I got ones that were.

Mini-split compressors come with all the refrigerant needed contained in the out door compressor unit. Once you have the lines evacuated you release the refrigerant into the copper lines and through the inside head units. When you take a mini-split out of commission you shut off the valve on the high pressure line of the compressor. You then run the compressor in shut down mode which pumps all of the refrigerant out of the lines/head units into the compressor then shut off the low pressure valve to keep the refrigerant contained in the compressor. I have looked at the CL used units also (for my shop) and always wonder if they were decommissioned properly? If they weren't decommissioned properly you will need several pounds of R410a which has been discontinued. Even if the used compressor was decommissioned properly you don't know if it was initially installed properly. If there was and trace of moisture in the line sets when the used system was initially installed the refrigerant will break down over time and cause problems.

If you get a used mini-split and install it yourself and it doesn't work do you have bad equipment or did you do something wrong? When I installed the 3 zone system the electrical connections were (left to right) 3, 2, 1on the compressor. The line set connections on the compressor were (top to bottom) 1, 2, 3. WTF? That one took me a good while to figure out!!! The 2 unit would always work fine but the 1 and 3 units would only occasionally work. Once I actually read the imprinted labels on the wiring and the line set plumbing I found line set/wiring 1 and 3 were switched.

Installing a 1 zone mini-split is a LOT easier than installing a 3 zone mini-split... at least for me it was.

My bathrooms don't have head units or any source of heat. The upstairs bathrooms are fine but the downstairs bathroom gets cold. The downstairs bathroom needs a space heater to keep the kids from complaining during the winter.

FYI, There are ducted mini-splits that can be used to pump warm/cool air into multiple rooms. You install these between the ceiling joists instead of a head unit on the wall.

The most labor intensive part was installing the line sets on the outside of the house to plumb the 3 bedroom headsets back to the common compressor. You have to be very careful to make sure you don't kink the lines. This is especially difficult if you have to go around a corner of the house. I installed my line sets in vinyl line set covers to keep the house looking nice and protect the line sets. Connecting the line sets to the inside head units was a good challenge.

P.S. Not to brag but I am a pretty accomplished handy man. The mini-splits were one of the more difficult projects because there was so much to learn. The pay off for doing it myself in $ saved made the project worth it for me.

I bought my Mitsubishi systems from AC Wholesaler in June of 2020: - https://www.acwholesalers.com/cooling/home-cooling.html

PRODUCTS

Qty	Description	Price
1 x	Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi 1/2" Condenser x 3/8" Line Set - Port Adapter - Flare Connections (MAC-A455JP-E) - Lift Gate Service: Yes, I'll Need A Lift Gate	$46.44
2 x	Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi GL-Series 6k BTU Wall Mounted Unit - For Multi-Zone (MSZ-GL06NA-U1) - Lift Gate Service: Yes, I'll Need A Lift Gate	$902.28
1 x	Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi GL-Series 9k BTU Wall Mounted Unit - For Multi or Single-Zone (MSZ-GL09NA-U1) - Lift Gate Service: Yes, I'll Need A Lift Gate	$496.63
1 x	Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi - 24k BTU - M-Series Outdoor Condenser - For 2-3 Zones (MXZ-3C24NA2) - Lift Gate Service: Yes, I'll Need A Lift Gate	$2,327.75

	Sub-Total:	$3,773.10
	Shipping:	$0.00
	Sales Tax: (Estimate)	$0.00
	Total:	$3,773.10

I bought the copper line sets from a different company and saved ~40% on them.

jbett98 · Dec 3, 2024

What year was the house built?

fredridge · Dec 3, 2024

jbett98 said:
What year was the house built?

1970

fredridge · Dec 3, 2024

MikeInOr said:
The Mitsubishi I installed with 2x 6000btu and 1x9000btu runs on a 24000btu (2.4 ton) compressor. A heat pump does not put out hot air like electric resistance heat instead it puts out warm air. We keep the head units running 24 hours a day and they run at a VERY slow rpm on the compressor and the head unit blowers. It might seem counter intuitive but it is very efficient this way. Instead of ramping up for a heavy load and constant power cycling like central HVAC it is a constant low load.

The better you size the mini-splits to the actual need the more efficient they are.

Both the Mitsubishi and Fujitsu will detect if the compressor coils freeze up and run the compressor backwards to melt the ice off the coils. I have never had a problem with the inside head units or compressor needing attention due to freezing up. My Mitsubishi and Fujitsu are both rated to work at a lower outdoor temperature than the cheap brands. Here in Central Oregon it will hit -5F or even -10F outside and they still run and put out warm-ish air but we fire up the woodstove or electric space heaters to augment the mini-splits when it gets this cold. Not even all of the Mitsubishi and Fujitsu mini-split models are rated for sub zero outside temps. I was aware of this and made sure I got ones that were.

Mini-split compressors come with all the refrigerant needed contained in the out door compressor unit. Once you have the lines evacuated you release the refrigerant into the copper lines and through the inside head units. When you take a mini-split out of commission you shut off the valve on the high pressure line of the compressor. You then run the compressor in shut down mode which pumps all of the refrigerant out of the lines/head units into the compressor then shut off the low pressure valve to keep the refrigerant contained in the compressor. I have looked at the CL used units also (for my shop) and always wonder if they were decommissioned properly? If they weren't decommissioned properly you will need several pounds of R410a which has been discontinued. Even if the used compressor was decommissioned properly you don't know if it was initially installed properly. If there was and trace of moisture in the line sets when the used system was initially installed the refrigerant will break down over time and cause problems.

If you get a used mini-split and install it yourself and it doesn't work do you have bad equipment or did you do something wrong? When I installed the 3 zone system the electrical connections were (left to right) 3, 2, 1on the compressor. The line set connections on the compressor were (top to bottom) 1, 2, 3. WTF? That one took me a good while to figure out!!! The 2 unit would always work fine but the 1 and 3 units would only occasionally work. Once I actually read the imprinted labels on the wiring and the line set plumbing I found line set/wiring 1 and 3 were switched.

Installing a 1 zone mini-split is a LOT easier than installing a 3 zone mini-split... at least for me it was.

My bathrooms don't have head units or any source of heat. The upstairs bathrooms are fine but the downstairs bathroom gets cold. The downstairs bathroom needs a space heater to keep the kids from complaining during the winter.

FYI, There are ducted mini-splits that can be used to pump warm/cool air into multiple rooms. You install these between the ceiling joists instead of a head unit on the wall.

The most labor intensive part was installing the line sets on the outside of the house to plumb the 3 bedroom headsets back to the common compressor. You have to be very careful to make sure you don't kink the lines. This is especially difficult if you have to go around a corner of the house. I installed my line sets in vinyl line set covers to keep the house looking nice and protect the line sets. Connecting the line sets to the inside head units was a good challenge.

P.S. Not to brag but I am a pretty accomplished handy man. The mini-splits were one of the more difficult projects because there was so much to learn. The pay off for doing it myself in $ saved made the project worth it for me.

I bought my Mitsubishi systems from AC Wholesaler in June of 2020: - https://www.acwholesalers.com/cooling/home-cooling.html

PRODUCTS

Qty Description Price
1 x Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi 1/2" Condenser x 3/8" Line Set - Port Adapter - Flare Connections (MAC-A455JP-E)
- Lift Gate Service: Yes, I'll Need A Lift Gate
$46.44
2 x Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi GL-Series 6k BTU Wall Mounted Unit - For Multi-Zone (MSZ-GL06NA-U1)
- Lift Gate Service: Yes, I'll Need A Lift Gate
$902.28
1 x Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi GL-Series 9k BTU Wall Mounted Unit - For Multi or Single-Zone (MSZ-GL09NA-U1)
- Lift Gate Service: Yes, I'll Need A Lift Gate
$496.63
1 x Kit MXZ-3C24NA2 MSZ-GL09NA-U1 2-MSZ-GL06NA-U : Mitsubishi - 24k BTU - M-Series Outdoor Condenser - For 2-3 Zones (MXZ-3C24NA2)
- Lift Gate Service: Yes, I'll Need A Lift Gate
$2,327.75

Sub-Total:
$3,773.10
Shipping:
$0.00
Sales Tax: (Estimate)
$0.00
Total:
$3,773.10

I bought the copper line sets from a different company and saved ~40% on them.

Thanks. I will stick with new. By brother in law did a 5 unit Mr cool so I know worst case he may be able to help, but he is a ways away and has a lot going on in his own life.

I did order some wall mounted heaters from Amazon for a couple hundred bucks and will use the wiring from the radiant ceiling thermostats and disconnect the ceiling part.

jbett98 · Dec 3, 2024

Do you have a popcorn ceiling texture up on your ceilings by any chance?

fredridge · Dec 3, 2024

jbett98 said:
Do you have a popcorn ceiling texture up on your ceilings by any chance?

No. It used to but not anymore.

jbett98 · Dec 3, 2024

Was the popcorn ceiling material checked if it contained asbestos before it was removed?

fredridge · Dec 3, 2024

jbett98 said:
Was the popcorn ceiling material checked if it contained asbestos before it was removed?

That, some flooring and something else. All tested and handled properly.

Are you an inspector?

The extra stuff took an extra month in a half to get done before we moved in and then were still living with a lot unfinished. Did a few more months of work and got fatigued. We are now getting to the point of wanting/needing to do lots of other stuff.