Help please. Ballpark estimate forRadiant Floor Heat System

[ron_marsh]

Hello! Newbie, building a 40x40 garage-workshop, oklahoma area, and was quoted $15k to $18k, for a 3-zone GeoThermal install, 3 tons.
I know much more info is required to accurately determine the precise system requirement costs, but could someone comment if this quote reflects an accurate estimate of the approximate cost of installing a basic garage radiant floor heat systen for a 40x40 layout, geothermal water-to-water in-floor system? Appreciate any feedback.

 

[Dagny]

Does it get cold enough in ok. To justify a ego. system.

 

[ron_marsh]

Note, this quote does NOT include cost of Ground Loops because our Electric Coop has a program where they will install, at no cost to me except for a $15/mo fee,
all the loop fields needed (one vertical loop per ton.)

 

[ron_marsh]

Our Electric Coop is really pushing Geothermal. Free loop install plus $450 - $650 cash rebate. per ton

 

[ron_marsh]

Okla doesn't compare to northern states weather-wise, but if install cost is not outrages, would like to have it. May be having a live-work space in one of the zones.

 

[Randy in Maine]

Well no matter what you are using for a heat source, some of the costs are about the same.

Figure out the square footage of the building. For you lets assume that is 1600.

2" of insulation under the slab = $1 per square foot = $1600. You put them in on top of the vapor barrier.

1500 feet of 1/2" Wrisbo PEX = 3 (rolls of 500 feet) x $375 = $ 1200 You put it in by attaching it to the woven wire or rebar with zip ties.

I would have my local heating guy make the incoming and outgoing manifolds for each zone. 3 x $250 would be my guess.

 

[ron_marsh]

Thanks Randy. I've done a fair amount of research and just cannot come up to the cost estimate being quoted, so I'm wondering what I am missing (estimate seems wacko to me, but have asked for
estimates from 2 sources and both have been in $15-$20k range, so don't know if I just happen to get twogoofballs, or if I am the goofball.)

Is the systems control package THAT expensive?

 

[Randy in Maine]

I am sure that the controls may be a bundle for a geothermal set up as there is not a ton of energy in 40º water vs what my little $2500 propane fired hot water systems puts out BTU wise. I think I am roughly 150K BTU or so. My 3 zone controls came to maybe another $1500 if that.

I am heating roughly 3000 square feet of well insulated house and garage in Maine for about $2300 a year in propane (600-700 gallons at $2.75/gallon). It would take a long time to beat that with geothermal.

Since you are in OK, why not heat AND cool it with those "mini-splits". I would still insulate and put the PEX in that slab for a future "Plan B", but that might get you through for a pretty cost effective comfort for a long time

 

[ron_marsh]

Yes, I've been looking at the mini-splits since I got the $15-18k estimates on theGeo/Radiant. I really like the idea of warm floors, but may be cost-benefit
detrimental. Stupid question, will the 2" insulation
under slab, without radiant floor, be enough to enable "conventional heating" to keep the slab at a comfortable temp during winter? I am planning a life/work space in one of the zones.
I'm an artist (ron=rhonda) who loves to go barefoot.

 

[ron_marsh]

Yes, I've been looking at the mini-splits since I got the $15-18k estimates on theGeo/Radiant. I really like the idea of warm floors, but may be cost-benefit
detrimental. Stupid question, will the 2" insulation
under slab, without radiant floor, be enough to enable "conventional heating" to keep the slab at a comfortable temp during winter? I am planning a life/work space in one of the zones.
I'm an artist (ron=rhonda) who loves to go barefoot.

 

[brewchief]

Well no matter what you are using for a heat source, some of the costs are about the same.

Figure out the square footage of the building. For you lets assume that is 1600.

2" of insulation under the slab = $1 per square foot = $1600. You put them in on top of the vapor barrier.

1500 feet of 1/2" Wrisbo PEX = 3 (rolls of 500 feet) x $375 = $ 1200 You put it in by attaching it to the woven wire or rebar with zip ties.

I would have my local heating guy make the incoming and outgoing manifolds for each zone. 3 x $250 would be my guess.

Pretty close numbers, internet shopping might get stuff a little cheaper but not by a whole bunch.
Double that number and it will be pretty close to installed cost, right around 7k

Quick interweb search puts a 3 ton water to water geo unit at around 3k, 3 zones equals 3 pumps at 100$ each plus isolation flanges at 45$ per pump, still need pump relays, good air separator fill and back flow, thermostats, expansion tank, etc.

On a normal boiler job it's common for me to have 1200-1500$ in small parts.

Say for examples sake 3k in heat pump and 1500 in other parts, 4500$ total, double that and add your 7k from the tube and insulation and your at 16k, right in the ballpark.

The hidden man hours spent designing, detailing a parts list and ordering it, running to the site to verify a pressure test or meet an inspector add up on this type of job.

We don't do geo but I'd say the prices are about what they should be.

 

[Randy in Maine]

At my place (1500 square foot house and 1200 square foot garage) it takes about 1 hour to raise the radiant floor heat 1º. I turn it on about Thanksgiving and turn it off about April. I have 3 zones, each controlled by a wall mounted thermostat. The floors are about 5º warmer than the air the thermostat sees. 65º in the house (wood floor). 60º in my wifes' stained glass room (tile floor), and 55º in the garage (concrete floor).

I also have 2 propane fire "fake woodstoves" in the house and stained glass room that will crank up the heat in that room if needed to about 72-74º (from 65º) in about 15 minutes. They heat the air up and make it very comfortable. The cats just sleep anywhere though. I find that if the floors are warmer than they are, it is too warm for me to sleep without overheating.

We don't really need air conditioning here at the beach in Mane though. We don't usually get hot and muggy for more than a few days at a time. About 65º as I write this....

 

[ron_marsh]

Randy, BrewChief,

Thanks both of you. These cost breakdowns and stats have answered a lot of my questions. This is a great resource, and I appreciate your time and experience which you have graciously shared. Tickled pink that I've found this forum! Thanks again, Rhonda {aka "Ron")