What heat source for radiant floor???

[GerryL]

I've read so many forums and gotten so many strong opposite opinions that my head is spinning! I'm looking for info from your experience to help me make a decision. Here's my situation; we just put up a 30x50 Steelmaster building for a workshop/storage building. We're in the hilltowns of western MA, so I'd heat approx Oct through March give or take a little on each end depending on the weather. So it's 1500 sq ft, 14' high at the center peak, floor is about 5" thick with 3 loops of 5/8" pex, all just under 300 feet long each, all in 1 zone. 2" insulation under the entire floor, 1" around the perimeter. Building will be insulated to R19 and will be pretty tight. It has one 10x10 insulated overhead door and 1 insulated walk in door. It will be a closed glycol system, no domestic water needs.
I've seen people say don't go with a hot water tank, use an on demand tankless like a new Takagi JR with modualting burner: I've seen just as many say no way, go with something like a Polaris water heater. I'm baffled by these different opinions.
Electric appears to be cost prohibitive for me, I think the delivered price is about 16.5 cents/kwh here. I'm not to keen on an oil boiler due to the space it takes with a tank, and the volatility of price. I've looked at outdoor wood and coal boilers, they seem to have a high up front cost then there is the ongoing labor. I'm leaning towards propane but I am concerned about an open flame unit as I'll be working out there and may have fumes/vapors from time to time (paint, gas).
If anyone has thoughts/experiences on operational costs of on demand vs tanked type heater, I'd love to hear your experience. It looks like I can put in a Takagi on demand for the least money, but I have no clue which method uses less fuel.
Thanks!
-Gerry

 

[bobs409]

I'd like to know this too. I have the tubes in the floor and am just waiting to see how costs go in the next few years as to what type I go with. Electricity is supposed to jump up in a year or two and oil & propane is high.


Bob

 

[tdkkart]

Do a search for "energy cost comparison" , you will be given a bunch of calculators that will show you cost/ 1million BTUs delivered. Plug in your current local costs for each fuel and it will show you the difference. Remember to consider the efficiency of each heating method.

 

[HoosierBuddy]

I don't have a cost comparisson for you, but my research into the same issue left me with the following opinions:

1. Water heaters are generally not designed to heat a garage. Unless the manufactuer specifically designs and markets their heater to work for space heating, I'd be leary of using it. Yeah it might work...but that's not what it's for.

2. Mixing domestic potable water and your heating water loop MIGHT be unsafe. Go to www.healthyheating.com and do a search for a POTENTIAL health issue.

3. A modulating boiler is the absolute best source to heat water for your hydronic heating needs. If you also have a domestic potabale hot water need (a shower or sink in the shop for instance), they make boilers that have a seperate heat exchanger just for that application.

I went with a Trinity TI150 and it's worked great for me. It's over 90% efficient and may qualify for Energy Star tax credits. They duct out the wall with PVC so nothing has to go through the roof....so that's cool. Also, you might check with your utility to see if they offer rebates. They aren't cheap...but you know a good boiler ought to last a long long time. You've spent a lot of money on your building...don't cheap out now.

Here's the NYthermal link on the Trinity Boiler. http://www.nythermal.com/Products/boilers/gas/trinity.htm

Phil

 

[kuhner]

I bought a Seisco electric boiler. Been pleased with it.

http://www.seisco.com/

greg

 

[GerryL]

Electric? What is the electric rate in your area? cents/kwh?

 

[5wndwcpe]

$300 tax credit will apply if you buy a new qualifying unit after January 1st 2009.

 

[Boiler Man]

Electric? What is the electric rate in your area? cents/kwh?

My rate is 6 cents per KW I live in freezing Winnipeg Manitoba I have and electric boiler. conceptmfginc.com . Works Great

 

[GerryL]

Wow, you guys get a deal! Here I pay 16.5 cents/kwh delivered.
I could never afford to run an electric boiler.

 

[Thomarann]

I put an NTI on-demand boiler in my 30x32 shop for in-floor heat as well as warm water.

It has only been running for a month so far so we'll see how it does when it is 40 C below outside. I also have a larger NTI boiler in my house basement to heat the basement floor, garage floor, and main floor and it has worked flawlessly for 2 years now.

Marc

 

[X...]

a friend of mine added a 40' x 44' x 16' Morton Bldg. onto his existing building...and used a hot water tank(gas) to heat that area with no problems...

here's an idea if you wanted to use an outdoor wood furnace...since their have been some boiler problems with some models...another friend of mine bought a Harmon wood/coal boiler, and built his own enclosure around it...

he saved about $3000 over the cost of an outdoor furnace...

 

[danski0224]

I've read so many forums and gotten so many strong opposite opinions that my head is spinning! I'm looking for info from your experience to help me make a decision. Here's my situation; we just put up a 30x50 Steelmaster building for a workshop/storage building. We're in the hilltowns of western MA, so I'd heat approx Oct through March give or take a little on each end depending on the weather. So it's 1500 sq ft, 14' high at the center peak, floor is about 5" thick with 3 loops of 5/8" pex, all just under 300 feet long each, all in 1 zone. 2" insulation under the entire floor, 1" around the perimeter. Building will be insulated to R19 and will be pretty tight. It has one 10x10 insulated overhead door and 1 insulated walk in door. It will be a closed glycol system, no domestic water needs.
I've seen people say don't go with a hot water tank, use an on demand tankless like a new Takagi JR with modualting burner: I've seen just as many say no way, go with something like a Polaris water heater. I'm baffled by these different opinions.
Electric appears to be cost prohibitive for me, I think the delivered price is about 16.5 cents/kwh here. I'm not to keen on an oil boiler due to the space it takes with a tank, and the volatility of price. I've looked at outdoor wood and coal boilers, they seem to have a high up front cost then there is the ongoing labor. I'm leaning towards propane but I am concerned about an open flame unit as I'll be working out there and may have fumes/vapors from time to time (paint, gas).
If anyone has thoughts/experiences on operational costs of on demand vs tanked type heater, I'd love to hear your experience. It looks like I can put in a Takagi on demand for the least money, but I have no clue which method uses less fuel.
Thanks!
-Gerry

You need to determine the heat load before anything else.

A water heater will do fine in a closed loop application, but it may not have the btu capacity to do the job (40k btu input x 60% efficient = 24k btu available).

Not all tankless heaters will do a radiant loop... they still have an open flame and are maybe 80% efficient.

A modulating boiler is the only way to go.

A Weil McClain Ultra is up to 98% efficient in a low temperature application, and includes many of the required controls like an outdoor reset. It also is PVC vented, so you can get outddor air for combustion... not sure if the burners are sealed- probably are.

With a boiler like that, you can add an indirect fired water tank for your domestic hot water needs.

$.02

 

[Boiler Man]

Nice set-up , How do you post pictures on this site. Thanks

 

[mrhaney]

coalman outdoor stoker boiler heat house ,shop and hot water,400,000/600.000 btu
http://www.outdoorstokerboilersofky.com/

 

[MN BIANCHI]

I am in the process of building a new toy shed/shop. I installed a 24 KW electric boiler. My electric cost is 5.4 cents per KW because it is interruptable. I will be using an LP gas unit heater for the backup system.

\

I am heating just under 3,000 sq. ft. The sytem uses 11 loops and 2 pumps.

 

[jklingel]

You need to determine the heat load before anything else.

A Weil McClain Ultra is up to 98% efficient in a low temperature application, and includes many of the required controls like an outdoor reset. It also is PVC vented, so you can get outddor air for combustion... not sure if the burners are sealed- probably are.

With a boiler like that, you can add an indirect fired water tank for your domestic hot water needs.

$.02[/QUOTE•• 98%? From where did you get that number? Man, that is as pretty as they get! That must then be a condensing boiler????

 

[GerryL]

Well I thought I'd update this thread since I started it some time ago; we ended up going with a propane boiler; this is a Munchkin. It's been running 3 months and we're happy so far. No domestic water, just radiant floor.

 

[trythis]

Do you have land? If you want to take advantage of a 30% uncapped tax credit consider a ground source heat pump (geothermal) If you have lots of land or a pond, it gets cheaper. Horizontal lops are a lot cheaper than vertical wells. You probably need 5 tons, since its so cold. Anyway, look in to the cost with that tax credit.
Your electric bills would be CHEAP. You could easily hook up a water chiller in the system and do air conditioning in the summer, but MA may not need that.
If anyone does geothermal, leave it set at the temp you want, recovery can take days.

just an idea for those interested in high upfront/low operating costs

 

[jvitez]

We have water to water open loop geothermal heat for our house, 4 zone fan coil high velocity duct type. It's a well to well system. Interestingly, cost was about the same here for a well to well vs closed loop slinky coil type set up, so we went with open loop not to have to haul water into a cistern like most do around here.

Our house is 40% larger than our previous house, and the energy bills are the same. New house does have more insulation, R60 ceiling, ~R32 high density spray foam in the main and second story walls, R24 fibreglass in the basement. Old house was built in 1995, so still quite efficient, with R20 wall, R40 ceiling, but only an oversized mid efficiency gas furnace.

So yes, a large up front cost but definitely a great payback on operating costs. We figure somewhere around a 10 year payback. Worth considering.

 

[7455dude]

I have some real world heat cost numbers:

5 years ago remodeled 50x110' pole shed into finished space for business,5500 heated sq. feet.

Blew in 8" wall insulation instead of bating, about 1000.00 extra. R-42 in attic, office space is 15' high ceilings. I would strongly recommend this in wall spaces.

6" of reinforced concrete over 2" dense foam, with 13 pex runs in 3 three zones, all zones continuously heated to 65-68 degrees.

Did not have Nat. gas available, went with (2) seisco 22kw mini-boilers on off-peak at aprox 4.0 cents per kw. They can cycle us between 4pm-10pm at their discretion.

two roof-top units with propane back-up heat and 10 tons total A/C.

Just came off first malfunction in 5 years, electronic control board (150.00). Replaced myself.

Live in Minnesota with many cold days to heat. We do not have an overhead door, I believe this is a huge culprit of heat escape for many, get a good door and reinforce and heat concrete under door so there is no heaving or gaps. As well as the door side seals.

We used The propane forced-air back-up the first two months we were open as the in floor-heat was not completed in time. 2 months propane usage was 700.00/ month,1100.00/month, November, December.

Since then we have only used the back-up system 2 days, control panel blown. 1 zone

Our average, "Heat only" costs for the two mini-boilers are 150.00/ month, with a high of 220.00.

Another advantage is if you do any kind of wet clean-up on the concrete floors they dry about 5 times as fast because of the warm concrete.

I cannot imagine where we would be with our energy costs and furnace maintenance had we gone with forced air only. Not to mention it is way more comfortable.

Jeff

 

[hyvolt]

Takagi on demand gas. Very cheap to run. Never had a problem with mine, in 5 years.(30x80 two story) Also put 1 in my buddys barn (60x40) with no problems in the past 2 years. Had a polaris water heater(threw it in the trash). My heater runs for 1-2 hours in the morning, may be 1-2hour late at night if it is below 20. keeps the shop at 70 all winter here in michigan.