New Guy - 1st Post - Gas Heat?

[Jet Sitter]

Greetings - I have been enjoying the entertaining and informative discussions in the forum and hope to join the ranks of a spa owner soon.  I have a question that I haven't seen discussed before - harass me if I missed it!

I am in the process of putting a radiant heat system in my house - with a gas boiler and hot water tubing the subfloor.  I could run an insulated loop to a hot tub with a heat exchanger to heat the water instead of using an electric heater, which should be cheaper to operate.  The temperature of the loop could be set quite high if I would like.  Has anybody done this?  Any pros and cons that I might want to consider?  Should I forget about it and just plan on using 240V electric power to keep things simple?  Thanks!

[Lars]

Sounds like a mess to me, I'd stick with the 240.

You're not putting the hot tub on top of the radiant flooring, are you?

[Jet Sitter]

Thanks Lars.  No, the tub will be outside, about 20 feet from the house.  I have seen a stainless steel heat exchanger advertised on-line that is used for swimming pools and supoosedly hot tubs.  You run hot water through it from your boiler and circ the water from the hot tub through and the heat is passed by the metal interface.  It sounds do-able and lower heat cost, but I am thinking it would be too quirky.  Probably makes much more sense to stick with the heating unit that comes with the tub rather than do soemthing oddball.  I thought I 'd ask anyway, just in case someone has done this successfully.

[Jacuzzi Jim]

 The company I work for also does radiant floor heat and we have done this in one spa and it worked pretty good. However it was a smaller sized spa not sure that makes a difference or not?  I believe they plumbed it as a separate zone?  I was not involved with how they hooked it up.

[RK23]

How expensive is that Radiant heating to install per square foot??

[Vanguard]

Generally, all of the hot tubs on the market today are totally self-contained.  They have everything you need already.  Unless you are buying a shell and doing the plumbing yourself, I'd stick with what comes on the spa.  The premium spas of today are very energy efficient.  Stick with a top brand and you won't have any problems.

[Jacuzzi Jim]

 Cant tell ya.  I do know it depends on the system and how many zones all that stuff.  To retro fit in an existing home is more expensive than new construction.  I dont have it in my home, from what I hear its very cozy.

[Lars]

Thanks Lars.  No, the tub will be outside, about 20 feet from the house.  I have seen a stainless steel heat exchanger advertised on-line that is used for swimming pools and supoosedly hot tubs.  You run hot water through it from your boiler and circ the water from the hot tub through and the heat is passed by the metal interface.  It sounds do-able and lower heat cost, but I am thinking it would be too quirky.  Probably makes much more sense to stick with the heating unit that comes with the tub rather than do soemthing oddball.  I thought I 'd ask anyway, just in case someone has done this successfully.

Seems like it would be a better fit for a traditional redwood type hot tub instead of a spa.

I can't imagine trying to stuff it in somebody else's equipment compartment.

[Jacuzzi Jim]

Seems like it would be a better fit for a traditional redwood type hot tub instead of a spa.

I can't imagine trying to stuff it in somebody else's equipment compartment.

 Should only be one line in one line out, Down fall is it does void the warranty.  The other downfall in his instance would be the distance? The one we did was really close to the house.   That being said, more and more people are using radiant heat for driveways to keep snow and ice off of.  Mostly really rich people.

[Lars]

Wasn't really worried about the line in and out, was thinking about how and where you'd mount the heat exchanger inside the equipment bay.

Just seems like a mess to me, for very little gain, if any.

[Jet Sitter]

RK23 - Radiant Heat costs vary greatly depending on system design.  Some folks do it themselves.  We're doing a basement remodel and have ripped off the ceiling exposing the subfloor above.  We wanted to get rid of furnace heat ducts becuase the space seemed cramped enough with 7' ceilings.  The space feels much nicer now with ducts out and a couple of beams raised so joists hang on them instead of resting on top.  Cheapest approach is to use a combination hot water tank and hang tubes in the joist cavity.  Other extreme is to attach aluminm plates to subfloor and insert tubing in slot for better heat transfer and use a condensing boiler with a separate loop to heat a water tank that has no heater.  We got bids that ranged from 15K to 35K for a footprint of about 1500 SF.  Once you buy the heat source, the cost for more SF is not much.  We couldn't justify the expense solely as a new heating system but losing the ducts and noise and dust was additional incentive.

Vanguard and Jacuzzi Jim's points about efficient self contained systems with warenty are good reasons to go the conventional route.  Lars hits the tip of the iceberg with configuration issues and figuring out how to do it.  Also have to figure out the best way to control the system and if things don't work right who is the guy to solve it?

I think we'll just plan on running 240V out to the location.  We're hoping to do the installation next summer but I wanted to ask the question now since the heating contractor is sizing the sytem and I wanted to factor in the hot tub if we were to go that route.

Thnaks for the advice!