I am breaking ground very soon on my 1400 sq' shop. I have been planning to do hydronic heat. But on the build green forum a member there who seems very knowledgeable says a ductless mini slit will be half the cost to run. I will be building with sip walls at r40 and I will insulate the ceiling well not sure to what value or type of insulation. I don't know much about the mini split and would like to hear other opinions.
in floor hydronic verse mini split
- Thread starter stealman
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kert
Well-known member
Wow, I was reading the same article today and getting ready to build an 1800sf shop with hydronic. I think I'm going to stick with the plan. I like the idea of the floor melting the snow on the cars and I love my heated bathroom floor so much in the house.
lzenglish
Well-known member
Mini splits are great, HW hydronic slab heat is absolutly great, but a "Ground Source Heat Pump" is the the best of the best in my opinion! No matter what you decide to do at this time, I woud add the pex to the slab during construcion, so you will have the option to add any other source of heat you desire at a later date. Congrats on your new build, and the best of luck to you.
Wayne
Wayne
larry4406
Well-known member
The mini-split gives you AC also right? Not so with the hydronic.
maxspeed96ct
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mini splits and heat pumps have come a long way , they are also 100%efficient . And you can get the equipment for around $1500 to do a avg size 2 car.
Im still not sold on the operating costs since natural gas is so much cheaper the electricity in my area . But for those that dont have gas availbile in their area heat pump/mini split might be the way to go.
Since im always wrenchin on cars (not enough height for a lift ), Im leaning towards doing the radiant, its a much more evenly distributed heat too.
keep us updated on your research , im starting my garage build in a month.
Im still not sold on the operating costs since natural gas is so much cheaper the electricity in my area . But for those that dont have gas availbile in their area heat pump/mini split might be the way to go.
Since im always wrenchin on cars (not enough height for a lift ), Im leaning towards doing the radiant, its a much more evenly distributed heat too.
keep us updated on your research , im starting my garage build in a month.
Manitoba or Miami? It does matter!
Radiant heat is wonderful. That said, it is most wonderful when it is matched with a mod/con high efficiency boiler with outdoor reset controls, etc. It is also best when it is cold enough out to bring the building up to temp and leave it there. How are you going to use the space? will it be full time use? You have lead/lag issues with slabs. Takes time to come up to temp and time to come down. In the shoulder seasons that can be an issue.
Ground source HP's are great but ridiculous money and you are going to be very very close to the efficiencies of the gshp with mini-splits at a fraction of the cost. Do you need cooling/dehumidification? If so, I'd go with the mini-splits. I represented Fujitsu for 12 years and like that brand. Top brands are Fujitsu, Mitsubishi (I see they are advertising at the Masters with Fred Couples) and Daikin.
Another option for heat that I am a big fan of is the Rinnai Energysaver. I've represented them for 21 years and heat my home with them and will heat the shop/garage with them next year when I build it. Mini-split/Rinnai is best in my case and the combination I have in my current and last home. YMMV, but these are worth a look.
I was talking with a contractor up Mt Lassen way this past week about mini-splits. He is an HVAC guy and a good one. He did a 3500 sq ft home with mini-splits last year. He said the system came in the same as a full ducted system cost wise, but was operating for less than half what a ducted system would have.
Radiant heat is wonderful. That said, it is most wonderful when it is matched with a mod/con high efficiency boiler with outdoor reset controls, etc. It is also best when it is cold enough out to bring the building up to temp and leave it there. How are you going to use the space? will it be full time use? You have lead/lag issues with slabs. Takes time to come up to temp and time to come down. In the shoulder seasons that can be an issue.
Ground source HP's are great but ridiculous money and you are going to be very very close to the efficiencies of the gshp with mini-splits at a fraction of the cost. Do you need cooling/dehumidification? If so, I'd go with the mini-splits. I represented Fujitsu for 12 years and like that brand. Top brands are Fujitsu, Mitsubishi (I see they are advertising at the Masters with Fred Couples) and Daikin.
Another option for heat that I am a big fan of is the Rinnai Energysaver. I've represented them for 21 years and heat my home with them and will heat the shop/garage with them next year when I build it. Mini-split/Rinnai is best in my case and the combination I have in my current and last home. YMMV, but these are worth a look.
I was talking with a contractor up Mt Lassen way this past week about mini-splits. He is an HVAC guy and a good one. He did a 3500 sq ft home with mini-splits last year. He said the system came in the same as a full ducted system cost wise, but was operating for less than half what a ducted system would have.
HoosierBuddy
Well-known member
You make no mention at all of how you would heat your water for your hydronic heat.
If electric: You would be MUCH better off going with the mini split.
If propane: might be a wash on cost and the mini split gives you a/c so probably still you'd be better off going with the mini split.
If natural gas? You'll have to do some figuring based on your power cost, etc.
Phil
If electric: You would be MUCH better off going with the mini split.
If propane: might be a wash on cost and the mini split gives you a/c so probably still you'd be better off going with the mini split.
If natural gas? You'll have to do some figuring based on your power cost, etc.
Phil
theoldwizard1
Well-known member
Propane is VERY expensive !
Father-in-law, in NW NC, has a heat pump. Neighbor has propane. Annual heating and cooling for the neighbor is 2-3 times.
There are 2 issue here. The source of the heat and how it is delivered. If you live in a cold climate, there is nothing like a radiant heat floor ! Not as big of a win in southern climates.
The lowest cost of operation is a probably a wood boiler, especially if the wood is free ! Wood pellets are also pretty cost effective. You can choose in floor radiant or just radiant.
A geothermal (ground water) heat pump has very low cost of operation. It is also probably the most costly to install. A/C is effectively free. You can do in floor radiant with geothermal but it is even more expensive and you don't typically get A/C.
Next highest cost of operation is likely natural gas (if available). Then a big jump to propane and finally electric heat.
Solar is a toss up. Solar will almost always need a backup heat source.
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kert
Well-known member
I'm surprised by those who say propane is much cheaper than electric in the midwest. I checked my electric bill, and after the first 300KWh, I'm paying $0.09/KWh. That is $0.026/1000BTU. I don't remember what I paid for propane this year, but $250/gal sounds about right. There are 91,000BTU/gal of propane, so that comes to $0.027/1000BTU. Of course that doesn't include the efficiency factor for the propane appliance (electric is 100% efficient on your end) so the propane number is optimistic.
If you go mini-split, your heat pump will have an COP (effective efficiency) greater than 1, which will make it cheaper to operate than an equivalent resistive or propane wall furnace.
One of the big advantages to radiant floor heating is that allows you to maintain a cooler temperature which reduces heat loss.
What I'd really like to see is a heat pump water heater/boiler with an outside evaporator like an air-air heat pump in heat mode.
If you go mini-split, your heat pump will have an COP (effective efficiency) greater than 1, which will make it cheaper to operate than an equivalent resistive or propane wall furnace.
One of the big advantages to radiant floor heating is that allows you to maintain a cooler temperature which reduces heat loss.
What I'd really like to see is a heat pump water heater/boiler with an outside evaporator like an air-air heat pump in heat mode.
aandpdan
Well-known member
Hydronic is great, there is nothing like having a warm floor,
But -
Are you going to keep the temp fairly steady? It can take hours for a slab to warm up. The mini split, blowing warm air would take the chill off a lot faster.
If you don't want a/c, and don't want to keep the floors hot, just put in a hot air furnace.
But -
Are you going to keep the temp fairly steady? It can take hours for a slab to warm up. The mini split, blowing warm air would take the chill off a lot faster.
If you don't want a/c, and don't want to keep the floors hot, just put in a hot air furnace.
Daikin Altherma!
kert
Well-known member
Thanks. Good to see that they are available. I'd guess I'm at least a year away from being ready to energize the tubes that I haven't put in the floor that hasn't been poured for the building I haven't gotten a permit for yet. Hopefully by that time the price may come down.
maxspeed96ct
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Hell do the radiant as a primary , and get a undersized minisplit for a secondary .
I actually like the idea of floor heat as primary and minisplit as secondary. Or more likely a wood stove for secondary. My thoughts are to run the floor heat at a somewhat cool temperature and fire up the wood stove to make the building more comfortable. I will probably put the tubes in the floor no mater what.
In reading about insulation I have always read to use 2" under the slab and more recently 3" or 4". But the darn stuff is so expensive. At what point is the extra insulation not worth the cost?
In reading about insulation I have always read to use 2" under the slab and more recently 3" or 4". But the darn stuff is so expensive. At what point is the extra insulation not worth the cost?
maxspeed96ct
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yupp, I might do the same . if you spend a few extra $ on a t-stat that has 2 stages, you can set it to maintain a low temp with the 1st stage using the slab radiant , like 45 degrees for example when your not working in the area.
And then if you are working in the area and want a temp of 65 but dont want to wait 2 hours for the radiant, the second stage of heat (min-split for example ) can kick on depending on what you set your differential for .
theoldwizard1
Well-known member
That is a wise decision !
I may have missed it, but where are you located ? MI, MN, WI, MA, etc absolutely !
BadgerBoilerMN
Well-known member
The cost of operation of any space heating system is mainly determined by the cost of available fuels. Secondly, the cost of operation has to do with the efficiency of conversion - fuel to heat. Finally, what the cost of space heating is determined by the efficiency and the method of distribution of heat.
There is no more efficient way to heat a living space than hydronic heating and where a concrete slab is being poured the clear choice is radiant floor heating. Radiant slabs are all about comfort. With the right heat source, nothing can compare. The fact is, any fuel may be used, be it electricity, natural gas, propane, wood, coal or buffalo chips.
As for response time. Any radiant panel will respond according to the design of the system and the control strategy utilized by the heat source. Forced air may raise the air temperature "quickly" but the determining comfort factor is really the average uniform surface temperature "AUST". Any garage used on a weekly basis can be maintained at a reasonable temperature - say 50°F - by simply turning the stat up 10 degrees the night before would put you in the warm zone.
Properly sizing the heat source and specifying the proper controls makes all the difference.
Remember, radiated spaces are more comfortable than those which are not.
There is no more efficient way to heat a living space than hydronic heating and where a concrete slab is being poured the clear choice is radiant floor heating. Radiant slabs are all about comfort. With the right heat source, nothing can compare. The fact is, any fuel may be used, be it electricity, natural gas, propane, wood, coal or buffalo chips.
As for response time. Any radiant panel will respond according to the design of the system and the control strategy utilized by the heat source. Forced air may raise the air temperature "quickly" but the determining comfort factor is really the average uniform surface temperature "AUST". Any garage used on a weekly basis can be maintained at a reasonable temperature - say 50°F - by simply turning the stat up 10 degrees the night before would put you in the warm zone.
Properly sizing the heat source and specifying the proper controls makes all the difference.
Remember, radiated spaces are more comfortable than those which are not.