Electric vs. Gas for radiant heat

[Flexia]

In the process of planning my garage out back. Not to sure about what utilities I will run out there. What are are pros, cons for gas or electric instant water heater for a 1200sq slab.

 

[koditten]

If gas is available, use it. To heat this with electricity you will need an exta large service.

Out of curiosity, what do you pay for a KW of electricity? In most cases, gas calculates to be cheaper.

 

[Highbeam]

If gas is available, use it. To heat this with electricity you will need an exta large service.

Out of curiosity, what do you pay for a KW of electricity? In most cases, gas calculates to be cheaper.

You might be surprised how little electric you really need. Lots of folks heating slabs with 7000 watt hydroshark boilers or even, gasp, 4500 watt water heaters. These are 30-40 amp circuits and when a home has a 200 amp main and many shops are 100 amp subpanels, 30-40 amps isn't too much. Since you are using radiant heat the system may run once a day or less. With some wise thermostat programming you can set up your system to only heat late at night which will free up the electric capacity during the working hours.

You don't mention if this is NG or LPG gas. If LP then it is not proper to conclude that gas is cheaper. In my area it is not, not even on a btu basis, and then when you factor in higher equipment costs....

If you have NG I would be putting the gas line in now.

 

[E.rodz]

I made the mistake of heating a slab with electric draws 40 amps when on super well insulated 700 sq. ft costs me about 200 per month in Mn. if it is avail. use gas . A few thoughts about electric if you have a 100 amp feeder and you are drawing 40amps while heating and you are doing some welding another 40 amps and your compressor kicks on thats all the power you have.

 

[HoosierBuddy]

I just received my annual mailing from the REMC this morning. Power cost has risen from 9 cents to almost 14 cents per KWH in the last 5 years. They didn't provide a prediction for next year...but since it's gone up every single year, I would expect it might continue.

The hard part about making an energy choice is, it normally involves predicting the future. Around here, Power is now 4 to 5 times as expensive as gas. There is no way in the world I would EVER install electric radiant. It is simply not cost effective.

If you want to use electric heat, get a high efficiency heat pump. It should use less than 1/3 the amount of power of radiant electric AND provide you a/c as well. If you can get NG (and can afford the premium for infloor radiant)...it is the berries. That's how I went in my garage, with a high efficiency natural gas boiler, and I love it!

Good Luck!

Phil

 

[Highbeam]

The only way to calculate cost of operation is to use a fuel cost calculator. You can't really compare buildings and locations unless you are neighbors with the same building.

I like this one:

http://www.hearth.com/econtent/index.php/articles/fuel_cost_comparison_calculator/

Also worth mentioning is the cost of equipment including the chimney.

In my shop I'm starting with a water heater but setting up the plumbing to be able to switch to propane or NG if it ever becomes available.

 

[theoldwizard1]

In most parts of the US natural gas is cheaper for heating than electricity.

 

[HoosierBuddy]

In most parts of the US natural gas is cheaper for heating than electricity.

Agreed, but for some without NG, electric heat may make sense.

My only point is a water heater uses electric resistance heating which is less than 1/3 as effective as a heat pump (or more) as long as it can keep up and doesn't revert to the "emergency" supplemental heat strips.

So, given the goal of any good heating system is to use the least energy possible...I (personally) would not consider using electric in floor hydronic heat....except perhaps using a heat pump water heater (which I don't know anything about except they are really expensive).

Around here, they used to use a lot electric resistance furnaces in houses or even electric resistance cable in the ceilings or baseboard electric resistance heaters throughout the house. All of those are gone now. People just couldn't afford to heat that way. There are better-much more efficient and/or cheaper options. NG would be 1. Heat Pump would be 2.

Phil

 

[Highbeam]

Agreed, but for some without NG, electric heat may make sense.

My only point is a water heater uses electric resistance heating which is less than 1/3 as effective as a heat pump (or more) as long as it can keep up and doesn't revert to the "emergency" supplemental heat strips.

So, given the goal of any good heating system is to use the least energy possible...I (personally) would not consider using electric in floor hydronic heat....except perhaps using a heat pump water heater (which I don't know anything about except they are really expensive).

Around here, they used to use a lot electric resistance furnaces in houses or even electric resistance cable in the ceilings or baseboard electric resistance heaters throughout the house. All of those are gone now. People just couldn't afford to heat that way. There are better-much more efficient and/or cheaper options. NG would be 1. Heat Pump would be 2.

Phil

You're right, you don't know much about heat pump water heaters. There is no common product available that uses a heat pump to heat water for floors. There are a few domestic heat pump water heaters that are very low output and depend on a backup resistance element for high/normal use times. The output is lower than a typical 4500 watt element which would be too small for most floor systems.

It would be great if the same technology that the minisplit air heating systems use could be applied to water heating. Shouldn't be a big leap. One rare european company does it, daikin, but they are rare and extremely expensive.

Until then electric water heating means resistance heating and when NG is not available, electric resistance heating can be the cheapest.

 

[tdkkart]

Agreed, but for some without NG, electric heat may make sense.

True, and one nobody has mentioned yet is the safety and convenience factors.There's alot to be said for no open flame and no carbon monoxide issues.
Electric tends to be be WAY less complicated, which typically means maintenance and repair costs are far less.

Alot to be said for pricing stability too. Around here electric and propane used to be nearly equal, but for the last few years propane pricing can be all over the map depending on who's farts stink and who's don't. Electric is state regulated, so while it may go up year over year, it's not likely to triple over nite like propane has a couple times.


Still never quite figured out how a heat pump creates heat for free.........or as close to free as some like to claim.

 

[HoosierBuddy]

You're right, you don't know much about heat pump water heaters. There is no common product available that uses a heat pump to heat water for floors. There are a few domestic heat pump water heaters that are very low output and depend on a backup resistance element for high/normal use times. The output is lower than a typical 4500 watt element which would be too small for most floor systems.

It would be great if the same technology that the minisplit air heating systems use could be applied to water heating. Shouldn't be a big leap. One rare european company does it, daikin, but they are rare and extremely expensive.

Until then electric water heating means resistance heating and when NG is not available, electric resistance heating can be the cheapest.

So they don't exist...except for the one that does exist? And (like I said) it's expensive. Sorry I was so misinformed.

Seriously though... when you say "electric resistance can be the cheapest". Given the fact that a modern heat pump will average about a COP of 3 to 5, and WORST CASE it will revert to 1.0 on emergency heat...how does it ever use as much electricity as resistance heating which always runs at a COP of 1.0?

Are you saying because the equipment is less expensive? If you're getting to your conclusion using a payback calculation (i.e. Heat Pumps are less expensive to operate but they cost more)....then please make that clear.

I'm trying to make a basic point, which I can tell you are probably already fully aware of...Heat Pumps use less power (by a lot) than standard electric resistance heating. It's a basic concept that people should appreciate before making their equipment choice.

Phil

 

[Highbeam]

So they don't exist...except for the one that does exist? And (like I said) it's expensive. Sorry I was so misinformed.

Seriously though... when you say "electric resistance can be the cheapest". Given the fact that a modern heat pump will average about a COP of 3 to 5, and WORST CASE it will revert to 1.0 on emergency heat...how does it ever use as much electricity as resistance heating which always runs at a COP of 1.0?

Are you saying because the equipment is less expensive? If you're getting to your conclusion using a payback calculation (i.e. Heat Pumps are less expensive to operate but they cost more)....then please make that clear.

I'm trying to make a basic point, which I can tell you are probably already fully aware of...Heat Pumps use less power (by a lot) than standard electric resistance heating. It's a basic concept that people should appreciate before making their equipment choice.

Phil

Okay. Yes, there is one oddball manufacturer in a foreign country that makes such a device called a heat pump water heater suitable for floor heat. That is why I said that there are no common sources of heat pumps to heat your floor. If you choose to import this device then you will pay a lot of money and there will be little or no support when it breaks. This eliminates that one oddball manufacturer from the candidate pool.

Your basic point is flawed as there is no available device that does what say to heat water. All currently available heat pumps heat air, not water, so comparing the air heating efficiency of this imaginary device does not contribute.

I am currently running wiring for my in floor electric resistance water heater. If a heat pump water heater, using modern inverter technology and typical floor heat btu output was available then I would love for you to show me.

We want the same thing but I have looked and came up empty handed.

 

[HoosierBuddy]

Okay. Yes, there is one oddball manufacturer in a foreign country that makes such a device called a heat pump water heater suitable for floor heat. That is why I said that there are no common sources of heat pumps to heat your floor. If you choose to import this device then you will pay a lot of money and there will be little or no support when it breaks. This eliminates that one oddball manufacturer from the candidate pool.

Your basic point is flawed as there is no available device that does what say to heat water. All currently available heat pumps heat air, not water, so comparing the air heating efficiency of this imaginary device does not contribute.

I am currently running wiring for my in floor electric resistance water heater. If a heat pump water heater, using modern inverter technology and typical floor heat btu output was available then I would love for you to show me.

We want the same thing but I have looked and came up empty handed.

Right. Agree.

So, the only thing I may not have made clear yet...and then I'll let you get the last word...

I categorically would not do what you are planning on. I'm not saying you shouldn't...I'm just saying "I PERSONALLY" would use an air-source heat pump (either standard or mini-split) for the same application because it would use roughly 1/3 as much electricity to operate.

Hydronic heat is great. It's uber comfortable. I agree your heating system will be superior in comfort, noise level, and probably service life to the choice I would make if I was you. But, I guess I'm cheap. I would not be able get around the cost difference to the power company....so I'd be in the market for an air source heat pump and would forgo hydronic all together if NG wasn't available.

Phil

 

[Highbeam]

Right. Agree.

So, the only thing I may not have made clear yet...and then I'll let you get the last word...

Your a goof aren't you?

There, last word

 

[HoosierBuddy]

Your a goof aren't you?

There, last word

I've been married TWICE. I know how this game is played.