New ICF House Baseboard Heat

Lineman63

I will be building a new ICF slab on grade home (zone 5 midwest) with R-10 insulation under the floor and R-55 in the attic. Would like to take advantage of reduced electric rates for heat and utilize electric baseboard heat. Most of the info I see online for rule of thumb sizing say 10 watts per square ft. for sizing elec. BB. heat, so my question is, how much can I down size on heating capacity for a house built to these standards. Attached are my floor plans, any help would be much appreciated.

hot_rod

Ick, electric basebored heat:) What about a hydronic radiant slab with an electric boiler.
How low are the rates? Any other fuel options?

Either way, you want to do a room by room heat load calculation. A few free online programs for load calc.


http://www.slantfin.com/products/virtual-heat-loss-calculator/

Lineman63

I was thinking with this much thermal mass/small house that hydronic radiant would be slow to respond and difficult to control. Rates are 6.4 ct per KWH. Propane is the other fuel option.

Canucker

Set the temp you want and use outdoor reset, not hard to control at all. No need to be setting back the temp all the time, that's what makes it difficult to control. Set it and forget it

Lineman63

My concerns are mostly with the open floor plan and other sources of heat from the kitchen and wood stove. I'm no expert but wouldn't concrete floor continue to emit heat for quite some time, even tho the t-stats are no longer calling for heat.

GroundUp

Not if the water temp is correct, no. Outdoor reset makes that pretty simplified. If you're burning the wood stove, it's obviously too cold in the space anyway right? Or is there another reason for wanting to dirty up the house with soot and ash?

Lineman63

Wow..., got something against wood stoves?

Zman

10 watts is 34 btus. There is no way your loss is that high. As suggested, start with a heat loss calc.

If you decide on a wood stove, think small, very small. With tight construction, a sealed combustion unit that pulls combustion air from the outside would be best.

If you go with electric, I would prefer electric panel radiators over baseboard heaters. Electric baseboard is a pretty harsh feeling form of heat.

I like this article https://www.pmmag.com/articles/83903-heating-a-thermos-bottle-house-br-john-siegenthaler

The attached sheet will help with fuel cost comparisons.

GroundUp

Lineman63 said:

Wow..., got something against wood stoves?

Not at all, I burn one myself. I'm asking why you would opt to feed a wood stove when you're basing the home's heating system off of electric baseboard. If you want to burn wood, burn wood with a stove sized to the load and forget the electric baseboard. Or better yet, go with a small wood boiler and hydronic baseboard if you're stuck on wood and baseboard. You'd never catch me living in a slab house with an unheated slab, but that's just me.

JUGHNE

That electric rate may not stay in the future.
If you commit your self to straight resistance electric heat via baseboards, there is no grace full way to change fuels in the event the rates climb up.

If you go with an electric boiler and infloor tubing heating, even hydronic baseboard or panels, you have options for the future.
Temp sensors in the slab, in the room and outdoors can control the heating to avoid the problems you anticipate. You need someone who knows what they are doing. With glycol antifreeze in the tubing you could also heat the garage floor.
(That is nice if you are in snow country.)
Some utilities offer even better rates if they are allowed to control stages of your boiler.

If you have heated floors you could go hours without power.
With BB heaters, they go off and cold like a light bulb.

In the future, if necessary, you could switch to an LP boiler or geothermal water to water heat pump......maybe air to water HP?

Without a basement to add ductwork and you would not want to add anything in the attic and punch holes in the ceiling you would be locked into the electric BB heaters.

Boiler could go in the garage near the sink or the laundry room.
Is that where the water heater is?
Where the water enters the house, often near the water heater, that needs to be a heated insulated room.
An LP boiler would need vented thru the roof or an outside wall.

I don't wish to criticize anyone's floor plan, but from about 40 years of being in the trades, putting 2 lavs in a 5' countertop, as in your master bath, has usually been regretted.
No place for make up, hair dryer, brushes etc.
Plus you lose storage drawers that could be on either side of a single lav basin.
Just an observation. IMO

Solid_Fuel_Man

I built a house to very similar standards which I currently live in with my family of 4.

There is no way, no how, I'd ever live on a concrete slab which was not heated. I have 2,200 square feet of slab heated with wood. I'd take advantage of that low electric rate as well and use an electric boiler. Use on a timer for off-peak rates too. That thermal mass is your friend no matter the heat source.

Heat the slab with water, heat the water with whatever you want.

At -45F my heat load is 14btu/square foot, that's 4.1 watts.

JUGHNE

Plus with the underfloor insulation he is planning, a major expense of the infloor system is already figured into the budget.

Lineman63

Zman



I agree the wood stove needs to be small and utilize a fresh air kit, I was thinking this one, Napoleon Banff 1100,(55,000 BTU max) . Think it will be to much?
For the electric baseboards, I was going to use this,
Qmark HBB Series Electric Hydronic Baseboard , hoping to moderate that harsh feeling.
That was a good article you referred to, I have read other articles stating the same.
The whole cost benefit ratio is a tough sell for radiant floors in this situation, one which is not an easy decision. I had radiant floor heat in my last house, designed and built by one of the best IMO. I know how good it can be. Thanks for the info.

Zman

I can't read the dimensions, looks like about 1,500 sq feet?
With that design you are likely 10-15 btu/ft. That would be 15,000-22,500 btu on design day. Not sure how low the wood stove will go.

Take a look at these for a low cost electric option. They produce nice even radiant heat and they won't melt the back of your couch. The electric hydronic models have about the same output per foot as traditional baseboard. I don't think you will see much difference.

Lineman63

Zman

I do not see your link for a low cost electric option.

Lineman63

GroundUp said
Not at all, I burn one myself. I'm asking why you would opt to feed a wood stove when you're basing the home's heating system off of electric baseboard. If you want to burn wood, burn wood with a stove sized to the load and forget the electric baseboard. Or better yet, go with a small wood boiler and hydronic baseboard if you're stuck on wood and baseboard. You'd never catch me living in a slab house with an unheated slab, but that's just me.



I'm not stuck on wood and baseboard. IMHO a wood stove puts out the purest most aesthetically pleasing form of radiant heat that there is.
Why would I want to be tied down to any kind of a wood burning devise as my primary heat source. That just would not work with my schedule.
I plan on using Mitsubishi mini-spit heat pumps for the primary heat, then using the baseboards on the coldest days when the heat pump becomes ineffective.

Lineman63

JUGHNE said

That electric rate may not stay in the future.
If you commit your self to straight resistance electric heat via baseboards, there is no grace full way to change fuels in the event the rates climb up.

If you go with an electric boiler and infloor tubing heating, even hydronic baseboard or panels, you have options for the future.
Temp sensors in the slab, in the room and outdoors can control the heating to avoid the problems you anticipate. You need someone who knows what they are doing. With glycol antifreeze in the tubing you could also heat the garage floor.
(That is nice if you are in snow country.)
Some utilities offer even better rates if they are allowed to control stages of your boiler.

If you have heated floors you could go hours without power.
With BB heaters, they go off and cold like a light bulb.

In the future, if necessary, you could switch to an LP boiler or geothermal water to water heat pump......maybe air to water HP?

Without a basement to add ductwork and you would not want to add anything in the attic and punch holes in the ceiling you would be locked into the electric BB heaters.

Boiler could go in the garage near the sink or the laundry room.
Is that where the water heater is?
Where the water enters the house, often near the water heater, that needs to be a heated insulated room.
An LP boiler would need vented thru the roof or an outside wall.

I don't wish to criticize anyone's floor plan, but from about 40 years of being in the trades, putting 2 lavs in a 5' countertop, as in your master bath, has usually been regretted.
No place for make up, hair dryer, brushes etc.
Plus you lose storage drawers that could be on either side of a single lav basin.
Just an observation. IMO




In 1989 the electric heat rate for REAs was right around 3.2 ct/KWH, now they are 6.4ct, yes it probably will go up, but at that rate I don't think I have to worry to much.
Letting a utility company control anything in my house sounds like a nightmare to me:)
With a small wood stove I could go days without power and not have to worry, sometimes in rural areas of the upper mid west ice storms can make that a reality.
LP..., really... you talk about rates going up and fluctuating. As for a geo. water-water heat pump, I would think the equipment cost alone would be staggering and cant even imagine the payback time for the size of house I am building.
I can handle the critiques for the floor plan, my thoughts for this floor plan are, energy efficiency, small footprint, a cost effective, robust structure that can give a person confidence when you don't have a basement to go to during storms.
A 60 in. vanity is not a big deal for us, we had one in our last house and got along fine. When I think about details like that where do you draw the line when deciding on a budget, every unnecessary square foot you can cut out of a house is less I have to pay in fees and taxes to fraudulent insurance companies and overspending governments entities. Just saying

JUGHNE

I just throw ideas out.
Our electric rate seemed stable at .10 and now is .17.
We are rebuilding our distribution system and that gets stuck in the overhead cost.

If your water lines are not near the perimeter of the building, you could go perhaps days without a freeze up. I have a "super" insulated house so to speak and feel confident freezing would be days away in my case. (northen NE).

Some buy LP at the right time and store 1000 gal.
The geo HP is popular now because of tax credits.

The vanity comment was not about the size, rather putting 2 basins in it. Limited counter top space was what I meant.
(Also the tax accessor counts all the sinks/basins )

What state are you is to get such good electric rates?

Solid_Fuel_Man

He is Canadian. That's why the minimum service entrance size is 200A in Canada. Electric resistance heat is very common in Canada.

They have cheap hydro power, but that is slowly changing. As the infrastructure is aging.

Canucker

> @Solid_Fuel_Man said:
> He is Canadian. That's why the minimum service entrance size is 200A in Canada. Electric resistance heat is very common in Canada.
>
> They have cheap hydro power, but that is slowly changing. As the infrastructure is aging.

That's Quebec only. I certainly don't have cheap electricity in Ontario, nor do I see all that much electric resistance heat. It does exist but it ain't cheap to run. The 200 amp panel is a code requirement for new builds

Solid_Fuel_Man

Ok, I was thinking there was more electric heat. I'm very close to the New Brunswick boarder and they have much electric heat there as well.

I stand corrected.

Lineman63

Jughne said

I just throw ideas out.
Our electric rate seemed stable at .10 and now is .17.
We are rebuilding our distribution system and that gets stuck in the overhead cost.

If your water lines are not near the perimeter of the building, you could go perhaps days without a freeze up. I have a "super" insulated house so to speak and feel confident freezing would be days away in my case. (northen NE).

Some buy LP at the right time and store 1000 gal.
The geo HP is popular now because of tax credits.

The vanity comment was not about the size, rather putting 2 basins in it. Limited counter top space was what I meant.
(Also the tax accessor counts all the sinks/basins )

What state are you is to get such good electric rates?




I am from Iowa, those cheap rates are for electric heat only. It requires a second meter loop, and a standard electric service at the normal rates as well. Its a bargain any way you look at it in my world.

Lineman63

Solid_Fuel_Man said
I built a house to very similar standards which I currently live in with my family of 4.
There is no way, no how, I'd ever live on a concrete slab which was not heated. I have 2,200 square feet of slab heated with wood. I'd take advantage of that low electric rate as well and use an electric boiler. Use on a timer for off-peak rates too. That thermal mass is your friend no matter the heat source.
Heat the slab with water, heat the water with whatever you want.

At -45F my heat load is 14btu/square foot, that's 4.1 watts.


Can you tell me what program you used to figure your heat load? And was it fairly accurate with the design temp ect. ?
Its my understanding that all the thermal mass throws an extra complexity into it.

Canucker

> @Solid_Fuel_Man said:
> Ok, I was thinking there was more electric heat. I'm very close to the New Brunswick boarder and they have much electric heat there as well.
>
> I stand corrected.

New Brunswick is the other province with cheap electric, I think they buy it from Quebec.

Zman

https://www.radiantsystemsinc.com/

jumper

I prefer ceiling height panels to baseboards. I also pay extra for two half sized panels for each zone so that one stays on continuously. I don't like slab heat because floating floors and rugs mess up performance.

Solid_Fuel_Man

> @Lineman63 said:
> Solid_Fuel_Man said
> I built a house to very similar standards which I currently live in with my family of 4.
> There is no way, no how, I'd ever live on a concrete slab which was not heated. I have 2,200 square feet of slab heated with wood. I'd take advantage of that low electric rate as well and use an electric boiler. Use on a timer for off-peak rates too. That thermal mass is your friend no matter the heat source.
> Heat the slab with water, heat the water with whatever you want.
>
> At -45F my heat load is 14btu/square foot, that's 4.1 watts.
>
>
> Can you tell me what program you used to figure your heat load? And was it fairly accurate with the design temp ect. ?
> Its my understanding that all the thermal mass throws an extra complexity into it.

I used the slant fin program. I knew I would be way under the smallest boiler anyway. My 70,000 btu/hr boiler generally modulates around 30% or less most days, so I'd say it's pretty on target.

With super insulation and large thermal mass, I've found that the heat loss is very linear. Also wind and infiltration are so low that there really is not a huge difference in heat load if its 20F or -20F.

I burn wood 90% of the time, so I'm very alert to how much heat (fuel) is needed and consumed on a daily basis. I really think infiltration has more to do with it than R values to a point. I have an R32 wall assembly, and R60 ceiling assembly. With very close to airtight construction. I built it myself with lots of attention to detail in the insulation phase.

Think of the linear heartless line as being much more flat, so percentage wise a doubling is really a small number. I've found the high mass to be very forgiving, much more so than some would believe. But that is with a less traditional envelope.

Solid_Fuel_Man

Also, when I build another house, the heated slab I'd definatly do again. Many other things I'd change though!