Geo-thermal heat and air

[DuaneBoyce]

Does anyone have experience with geothermal heat. What do you think and would you do it again? [img]/forums/images/icons/confused.gif[/img]

[Tevi]

My neighbor has and it's great.I don't think it's worth the money.A Carrier dealer I deal with said the reason Carrier hasn't got into it it because it's not cost effective.You are better off using the extra monet for a higher insulated house

[jetlag]

I have it, and I'd do it again.

[Pat]

Mixed reviews... My original design called for three ground sourced heatpumps. Lenox came out with a family of heat pumps that does a tad over 19 SEER. We crunched the numbers. We went with two Lenox air to air units and one WaterFurnace brand geothermal heat pump. The breakeven time on the geo unit compared to the Lenox air to air is 20 years or the lifetime of the unit so it is not a monetary savings for us. We retained the WaterFurnace unit because we have hydronic tubing in some of our slabs, shower walls, ceilings of some rooms and need hot water. I have a personal pref for hydronic heat. This is for the climate of south central Oklahoma.

If we were farther north then ground sourced heat pumps are good heat sources and the numbers would favor them over the air to air units. For us it was a wash but we need the hot water for the hydronics and I like free hot water in summer and my personal pref for DUCTLESS heat.

I had a local Lenox dealer (who did not get the job) that was a geo expert and promoter but was convinced that hydronics would not work in our climate. I hired one of the best in this end of the world and think I will be happy for a long time.

In our new construction(see Oklahoma farmhouse thread in this forum) the geo unit is THE MAIN unit. The house is zoned with electrically controlled dampers and I expect to NOT use one or both air to air units for reasonably extended periods of time.

Geo isn't the only posible right answer but it can be as good or better than air to air heat pumps in many instances.

Beware the disparaging comments of undereducated installers/sellers of HVAC equipment. There are more who are NOT DECENT HVAC ENGINEERS/DESIGNERS THAT THOSE WHO ARE BY A WIDE MARGIN. For many, if they aren't any good at it then the whole idea is a bad one.

Check ouit the RPA (Radiant Panel Association) web site. There are some geo experts there.


[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[traders]

There is nothing in the building industry that will save you more money over it's lifetime than a geothermal system. The government is now giving a 30% tax credit for the installation of a geoexchange system. There are often State and local rebates and credits that help overcome the added initial expense of a geo system. There is a company that sells the equipment that will enable a good do irt your selfer install one. look at www.arit.com geothermal heat

Traders

[Pat]

Did you notice you were posting to a thread with no activity since my last post about 4 years ago?

Wanna talk GEO? OK. Hydronics, OK.

Geothermal can be a good deal. Hydronic heat can be very comfortable but subject to overheating when outdoor temps jump up quickly and can be too cool when temps are falling quickly because of the lag in heating or cooling a slab. Some of my spaces (three rooms) have in ceiling heat and respond much more quickly to changing conditions. I have forced air (heating and cooling) in the hydronic heated spaces with separate thermostats for each system. By setting the hot air stat a couple degrees below the hydronic stat the hot air will keep the room from getting too cool when temps drop more quickly than the in-slab hydronics can track sufficiently.

It is hard to argue against super insulation and infiltration free construction. They have no particular "life cycle", no maint, no operating costs. If a space is so well insulated and tight that you could heat it with a candle and cool it with an ice cube then the means by which you provide the heating and cooling and the efficiency of that supply begins to be less important.

Of course if the space is so tight you pop your ears when you close the front door then you need a continuous supply of fresh air delivered reliably by some other means than the infiltration you eliminated when making the house tight. Either an ERV or HRV will do the job. My ERV runs 24-7 at under an amp at 120 VAC.

Just having a geothermal heat source does not make your overall system efficient or effective. Still the system design and operation has to be done properly or you can kiss the theoretically available advantages good by.

I need to go down in the basement and throw the summer winter switch to winter position so my geothermal heat pump will heat the water for the storage tank so the hydronic system will have some hot water to distribute. I looked at the month's weather predictions day to day and although we will have some more days in the 70's the trend of overnight temps is definitely going to be down. Just 3 days ago it was 82F in the early PM and then in the 40's the next morning (along with nearly 6 inches of rain in two days.)

Pat