Well, $10k 18 years ago is worth at least $30k today. So if your friend saved more than $30k in utility bills over the last 18 years, then this would be entering positive ROI territory.

not quite so radical, though you do bring up a good point.
have a look here http://www.dollartimes.com/calculators/inflation.htm
According to this calculation;

$10,000.00 in 1995 had the same buying power as $15,337.41 in 2013.
Annual inflation over this period was 2.40%.

Keep in mind the boiler is also removed from the cost.
So, ROI land? I think so.
At the time the whole system ran about 25k
Dan



Dan

We typically target between 10-15% for our investment ROIs, but that's a personal investment criteria. Yes, the concept is the same, but one has to do their own ROI analysis to make their right call.

The other thing that has to be considered is how much of the utility cost savings is directly/solely the result of spending the $10K on geo? Often times, just improving the building insulation significantly reduces utility cost. And these days one also has to seriously look at mini splits versus using geo or using an under-floor hydronic radiant system from a ROI perspective.

We believe that a slab hydronic radiant system is likely impossible to beat from a ROI perspective and certainly impossible to beat if properly accomplished as a DIY project by a competent DIYer. Furthermore, we think a slab hydronic radiant system beats everything relative to comfort which also needs to considered too. A slab hydronic radiant system that is properly designed to allow taking full advantage of a modulating/condensing boiler and is also augmented with passive solar heat gain hits the sweet spot relative to providing maximum efficiency with minimal maintenance/operational cost.

Dan - any idea of the maintenance cost of the system over those ten years?
Would you thing it was the same as a boiler system, lower or higher?

A slab hydronic radiant system that is properly designed to allow taking full advantage of a modulating/condensing boiler...

What if there is no natural gas available?

If you feel the need for flame ICF, most gas boilers will operate on either natural gas or propane. You know you have an efficient gas boiler when you can use PVC for the exhaust vent. There are also electric boilers that are worth considering. In fact, some of our customers who also have hydroelectric on their property (our favorite project) often prefer electric boilers.

The geo system we did some years back to my knowledge has had minimal service, I did not get involved with additional systems, am a boiler guy. That said I enjoyed the system and its workings, we farmed the heat pump and loop portion to a local guru at the time Sean Hogan, years back, that was the 10k portion, total system complete was about 25k

A condensing boiler, propane or natural will need a cleaning every 2 years or so, ignitors and flame rectifiers as well will be changed or checked.
Geo systems seem to have a value price point in that a small system may not be cost effective. I may be wrong there though as smart products keep hitting the market place.

That said I am working on a home project we are building with #2 75 gallon heat pump DHW tank systems, both have heat exchangers in place, both tanks are in line to the residence domestic h20. The DHW heat pumps water to air system may prove to be a cost effective solution for small supplemental systems.
Tank one is dedicated to house DHW, tank 2 has the opportunity to supplement the electric boiler(in-floor), using heat exchanger built in to the 75 gallon tank.
House has a 5,000 watt grid tie PV system to of set electric, house also has a small 2 ton heat pump forced air system (it was in our shop, needed a home).
Overkill, yes, but it is an experimental house, should be low cost to heat and offer up some interesting heat options. May add a solar drain down to tank 1 as it also has a built in heat exchanger coil that currently is un used.
The beauty of DYI is you can get fairy off track and creative,
Dan

some of our customers who also have hydroelectric on their property (our favorite project) often prefer electric boilers.

Okay, but I have to imagine that would be cheap electricity. What about the cost of delivered propane and resistance heat with regular utility rates? When do you go from flame to heat pump?

I would say only a good ROI analysis that includes all the associated system acquisition costs and all the associated system operational costs will correctly answer that question, and the answer will vary significantly by location because of the variability in labor and utility rates. If you are in an area where supply/demand doesn’t create cost effective heat pump installation/servicing, that may be a motivating factor.