DIY Hydronic Floor Heating - Page 43

randen · 02-27-14, 06:06 PM

Just for a little comparison our home is about 3600 sq ft. and 2 x 6 construction wrapped in a layer of 2" foam with stucco finish and well sealed. The home is heated in floor with a 6" concrete slab and all covered with tile.

Geo thermal and solar hot water. $280.00 per month (4 month winter) for electricity to operate the Geo thermal heat pumps.

The cons: lots of glass, Expansive glass block wall (R3/4) Open space lots of wind.

The pro: Oil heat would have been $6100.00

Awesome work Vlad

Randen

Vlad · 02-28-14, 01:50 AM

Quote:

Originally Posted by AC_Hacker

I'd have to add to what Vlad has said, by noting that his whole house is new-built with 6" studs, 24" spaced walls, insulated with mineral wool, double glazed windows.

And also Vlad is a total fiend when it comes to sealing air leaks. I've never seen anyone so thorough with a can of foam.
-AC

My walls are R22 Roxul insulation and roof is R40. As I said before my crawl space has no insulation and first floor is exposed to this cool place.

Quote:

Originally Posted by AC_Hacker

Hey Vlad, how many Therms of gas did you burn during the months of December also for February? Please include the billing dates for Dec & Feb. Also your zip code or equivalent.

I've come up with a very interesting way to do a heating analysis for your house.

Best,

-AC

Here are some gas info coldest Feb 2013 11 GJ low summer Jul 2013 4.5 GJ a month.

It is hard to estimate because we use a lot of gas for cooking cloth drying water heating etc. 4 adults and 2 toddlers.....

On average during heating season it adds about $70 max to gas bill

buffalobillpatrick · 03-29-14, 01:40 PM

I have designed & installed 2 working radiant floor systems. Both at 8,500' altitude zone 5, high winds often in Winter.

1st in in my current house, The upper 2 levels (2,000ft2) is heated via suspended 1/2" pex 8" OC under sub-floors. 2 runs between 16" OC TJI floor joyce. At bottom of 4" air gap below pex I have Reflectex, then sheetrock for ceiling below.

Roof is about R50 on average, walls R35, windows are tripple pane argon filled + outside 1/4" tempered storm windows (due to wind gusts >125mph)

The 3rd level is 1,020ft2 basement which is 5' below grade, 3' above. Walls are sheetrocked R18 ICF. Slab floor is insulated underneath with 4" XPS. Enough heat comes down through ceiling in Winter to keep basement @ 64*+-2*F

This system works well @ design temp. of 0*F & wind of 50mph. Using about 20MBH (20Kbtus) My 40MBH boiler runs at about 50% duty cycle at design conditions.
All floors are tile & surface temps. never go above 75*F.

This requires 145*F hydronic water temps at design, my LP boiler does not condense so it works just about as Eff. @ 180*F as it does at 130*F.

BUT, I wouldn't do suspended pex subfloor heat again.

2nd house is my neighbors 3,500ft2 log home, did this one with pex in concrete slab with 2" XPS under, he is penny-wise pound-foolish & this is all he would pop for.

His house is pooly insulated & has major air infiltration in wind, I don't realy know if he payed off building inspector?

His condensing (marginally) 150MBH boiller keeps up but he has to overheat his hickory flooring. He use about 4-5X LP vs my house.

BBP

buffalobillpatrick · 03-30-14, 02:37 PM

A/C, I don't recall if you have implimented your radiant floor yet?
Your last post regarding build-up seems like it was months ago.
The build-up & close spacing looked "GREAT" to me for your situation & requirements.
You will have slightly less heat transfer than if imbedded in concrete, but will have an advantage of quicker responce to changing weather.
Any updates?

AC_Hacker · 03-31-14, 12:31 AM

Quote:

Originally Posted by buffalobillpatrick

A/C, I don't recall if you have implimented your radiant floor yet?
Your last post regarding build-up seems like it was months ago.
The build-up & close spacing looked "GREAT" to me for your situation & requirements.
You will have slightly less heat transfer than if imbedded in concrete, but will have an advantage of quicker responce to changing weather.
Any updates?

I am preparing the room for the floor. I've put in he electrics, now I'm insulating with some kind of board to go up on the walls. Right now I'm on a tight budget, and it's my policy to not borrow money, so I make progress when I can... which means it's going slowly.

This week's victory was putting in a pretty high performance window with triple glass and double low E. I have also reduced the glass area of the room, possibly more than I anticipated.

My decision to do built up is based on the fact that my house is very old (120 years), and the foundation is not the best (basalt rock & river sand mortar). I did a calculation that 1.5" on my 12' x12' room would weigh 2700 pounds, which I'm not comfortable with... gypcrete wouldn't save much weight at all.

So, built-up will be the way for me. I sure have thought about it, and a wet system would be cheaper and quicker, and maybe even more efficient.

So, I have been watching Daox's office project (which is similar to Vlad's). I really like how he's going about it, and mine is going to be along the same lines.

My strategy is to increase the R-value under the floor and decrease the R-value on top of the floor.

Best,

-AC

Mikesolar · 03-31-14, 05:46 AM

AC, gypcrete is 40% less weight than concrete and 2700lbs is diddly if your joists are not at their limits. Unless you really know that the stones are in a precarious state, I wouldn't worry too much.

I'm looking at buying a 175 year old house built on stone with what they call a "flow through" foundation. A river seems to run through it at some times of the year but nothing has moved upstairs. The walls and door frames are all straight.

It is not recommended to use regular concrete under less than 2" BTW (if that is what you were thinking).

Drake · 03-31-14, 07:27 AM

Mikesolar, is that rec on regular concrete in regard to radiant efficiencies or structural( like cracking) do you know?

buffalobillpatrick · 03-31-14, 11:18 AM

I have read about DIY light weight mud: As I recall, you substitute pearlite for the gravel.
Lowe's sells pearlite in bags fairly cheep.

http://www.perlite.org/library-perli...e-Concrete.pdf

More perlite % = lower weight/strength/thermal conduction

AC_Hacker · 03-31-14, 11:33 AM

Quote:

Originally Posted by Mikesolar

AC, gypcrete is 40% less weight than concrete...

Correct me if I'm wrong here...

Density of gypcrete is 110 lb/cu ft

Density of concrete is 150 lb/cu ft

Density difference = 150 - 110 = 40 lb/cu ft

percent difference = (40/150) * 100 = 27%

Where did I make a mistake?

Gypcrete would have to have a density of 90 lb/cu ft. to be 40% lighter.

-AC

AC_Hacker · 03-31-14, 11:56 AM

Quote:

Originally Posted by buffalobillpatrick

...More perlite % = lower weight/strength/thermal conduction

Yes. I think that the idea is to get better conduction, ant the more perlite that is added, the worse the conduction.

I'm seeing perlite touted as a thermal insulator.

Shouldn't I be going the other way with a radiant surface?

-AC

02-27-14, 06:06 PM	#421
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 657 Thanks: 9 Thanked 191 Times in 129 Posts	Just for a little comparison our home is about 3600 sq ft. and 2 x 6 construction wrapped in a layer of 2" foam with stucco finish and well sealed. The home is heated in floor with a 6" concrete slab and all covered with tile. Geo thermal and solar hot water. $280.00 per month (4 month winter) for electricity to operate the Geo thermal heat pumps. The cons: lots of glass, Expansive glass block wall (R3/4) Open space lots of wind. The pro: Oil heat would have been $6100.00 Awesome work Vlad Randen Last edited by randen; 02-27-14 at 06:17 PM..

03-29-14, 01:40 PM	#423
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	I have designed & installed 2 working radiant floor systems. Both at 8,500' altitude zone 5, high winds often in Winter. 1st in in my current house, The upper 2 levels (2,000ft2) is heated via suspended 1/2" pex 8" OC under sub-floors. 2 runs between 16" OC TJI floor joyce. At bottom of 4" air gap below pex I have Reflectex, then sheetrock for ceiling below. Roof is about R50 on average, walls R35, windows are tripple pane argon filled + outside 1/4" tempered storm windows (due to wind gusts >125mph) The 3rd level is 1,020ft2 basement which is 5' below grade, 3' above. Walls are sheetrocked R18 ICF. Slab floor is insulated underneath with 4" XPS. Enough heat comes down through ceiling in Winter to keep basement @ 64+-2F This system works well @ design temp. of 0F & wind of 50mph. Using about 20MBH (20Kbtus) My 40MBH boiler runs at about 50% duty cycle at design conditions. All floors are tile & surface temps. never go above 75F. This requires 145F hydronic water temps at design, my LP boiler does not condense so it works just about as Eff. @ 180F as it does at 130F. BUT, I wouldn't do suspended pex subfloor heat again. 2nd house is my neighbors 3,500ft2 log home, did this one with pex in concrete slab with 2" XPS under, he is penny-wise pound-foolish & this is all he would pop for. His house is pooly insulated & has major air infiltration in wind, I don't realy know if he payed off building inspector? His condensing (marginally) 150MBH boiller keeps up but he has to overheat his hickory flooring. He use about 4-5X LP vs my house. BBP Last edited by buffalobillpatrick; 03-30-14 at 02:40 PM..*

03-31-14, 11:18 AM	#428
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	I have read about DIY light weight mud: As I recall, you substitute pearlite for the gravel. Lowe's sells pearlite in bags fairly cheep. http://www.perlite.org/library-perli...e-Concrete.pdf More perlite % = lower weight/strength/thermal conduction Last edited by buffalobillpatrick; 03-31-14 at 11:50 AM..

03-30-14, 02:37 PM	#424
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	A/C, I don't recall if you have implimented your radiant floor yet? Your last post regarding build-up seems like it was months ago. The build-up & close spacing looked "GREAT" to me for your situation & requirements. You will have slightly less heat transfer than if imbedded in concrete, but will have an advantage of quicker responce to changing weather. Any updates?

03-31-14, 05:46 AM	#426
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	AC, gypcrete is 40% less weight than concrete and 2700lbs is diddly if your joists are not at their limits. Unless you really know that the stones are in a precarious state, I wouldn't worry too much. I'm looking at buying a 175 year old house built on stone with what they call a "flow through" foundation. A river seems to run through it at some times of the year but nothing has moved upstairs. The walls and door frames are all straight. It is not recommended to use regular concrete under less than 2" BTW (if that is what you were thinking).

03-31-14, 07:27 AM	#427
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	Mikesolar, is that rec on regular concrete in regard to radiant efficiencies or structural( like cracking) do you know?