How many gallons of hot water do you estimate you will need on a daily basis? The three systems you are proposing seems to be overkill for domestic hot water usage for 2-3 people.

How much will your hot water system cost and how much do expect to save versus a conventional 40 gallon electric hot water heater?

Home Power magazine has featured energy efficient homes with ground-source heat pumps and solar thermal. You might check them and other sources out. I think that tank type point of use heaters do not fit well. In addition, you probably pass the point of economic return when you install two types of energy efficient water heating. The equipment costs get too high. My understanding is that the cost of PV panels has gone so low that installing PV and a conventional electric water heater makes more sense than solar thermal for DHW. I'd look carefully and run your own numbers to be sure.

I had read someplace that total water usage for a 2 person house is 65 gallons a day, not sure how much of that is hot water.

I'll look up home power magazine. Thanks.

I had looked into point of use heaters with tiny storage - talked to the company that makes them and found out that they were not the right unit for me, so I am not considering the ones with tiny storage.
Mike - you are right about costs. I am trying to optimize by sharing the tank between two sources. There is nothing extra to be done for geothermal desuperheater, it is already in the system. Solar will help when geo is not running. Solar has $1200 rebate in NJ.

Having said that, I have to admit that I haven't done detailed calculations of costs and ROI etc. I was trying to come up with a configuration first so that I could add up the costs.

Thanks.

I am also in NJ. I have seen solar several photo voltaic panels in my area, but only know of one house with a solar hot water heater. It is used to heat the water for a swimming pool and is not connected to the domestic hot water.

I assume the house will have no access to natural gas. If it does then you should rethink your plan.

My utility provider is PSE&G. I am paying about 18 cents per kWh. Assuming this electric rate, I estimate by using a conventional 40 gallon electric hot water heater your monthly cost for hot water will be about $60 per month. This you one data point for your ROI calculation.

Do you know the costs for the geothermal system? They can be quite expensive even after the federal tax credit.

Interesting observation Mike.

You are right about NG, there is no supply. Neighbors use propane.

Mine is JCP&L and I think my rate is in neighborhood of 14c.

Maybe I shouldn't introduce solar into the mix at all and just use instant in conjunction with geothermal.

Geothermal is pricey indeed. I had to jump through hoops to get it down to a reasonable number. Bought the system from another state, my well guy will be drilling for the loops as well. Another company will install the system and yet another one will install the ducts. Lets hope it all comes together. System is being delivered tomorrow. If you care to know the details of costs and company names etc., let me know.

You have three contractors involved for the geothermal system and you bought the equipment yourself? I hope this goes well for you and there are no installation problems.

Please share the details. I am curious to know what you consider a reasonable number.

I am not a geothermal expert, but there are some readers of this forum who can offer advice.

If your cost per kW is 14-cents then the cost per kW of heat delivered into your home should be about 3.9 cents/kW of heat delivered through your registers with a geothermal heat pump COP of about 3.6. ThatâÂÂs not too bad.

You would do well to plumb the desuperheater to a buffer tank (40-gal) supplying an active tank (60-gal). I would suggest leaving out the rest of the stuff (solar, instantaneous gas etc.), if you really want hot water the second you open the tap you could install a hot water recirculation system. A programmed hot water recirculation pump and insulating all associated pipe runs would save energy as well.

As for 3-contractors involved in the project, it not unusual to have 1-contractor to drill the boreholes and install the ground loops, 1-contractor to install the heat pump and mechanical room equipment and start-up with a third contractor to install all the duct work.

SR

Here is a link that might be useful: Grundfoss DHW Recirculators

I have no experience installing a geothermal system. What happens if the system is not performing well? Which contractor do you call first? How do you avoid having one contractor putting the blame on one of the other contractors? It is not an optimal situation in my opinion.

This post was edited by mike_home on Sat, May 11, 13 at 12:34

I agree that having 3-contractors may not be ideal. However, it may not be easy to find one HVAC contractor that will install the HP, owns and operates their own drilling equipment and also cuts sheet metal for all ductwork installation.

What often happens is that you would sign a contract with the HVAC installer for the total system installation and he would sub out the drilling/ground loop installation and duct design with installation to yet another contractor that specializes in duct design and fabrication. Should there be any problem you call the HVAC contractor that you signed the contract with and it becomes his problem.

You could also handle it like the OP of this thread and it becomes more like a small commercial project but it means more responsibility for the homeowner. It should all work out fine if heâÂÂs done his homework and has hired the right people - who have in turn done their homework, are properly trained, accredited and experienced!

I like to have at least 1-meeting with everyone on-site to discuss and run through the project together, to toss ideas around and to solve potential problems before they can happen. That way thereâÂÂs less drama and stress when itâÂÂs âÂÂShowtimeâÂÂ.

SR

Here is a link that might be useful: International Ground Source Heat Pump Association

Good points. SR, Mike. I was very keen on getting a single company to take care of it all. Best estimate I got for that $51k for a 4 ton water to air system with horizontal loops.

By splitting it up, I could get the system for 10k. 4 wells for 10k. System install and ducting for about 11 (not final yet).

AJ

That's a significant savings. You should be eligible for the 30% tax credit on the equipment, trenches, and installation costs. The duct work itself would not be covered.

Which geothermal system did you buy? Will the manufacturer honor the warranty given you bought it yourself? Did you do your own Manual J and Manual D calculations?

Indeed a significant difference. I bought Climate Master Tranquility 30 - 4 ton system. Bill of sale says that it has warranty.

My Architect (not primary but an out of state, brilliant architect from these forums) helped me calculate the healing/cooling loads - in fact he designed the energy efficiency aspect of the house. In fact, he designed most of the house too.

I had assumed that duct work would be eligible too - I will double check before I claim tax credit. Thanks for mentioning it.

You are getting a geothermal system which after tax credits is not much more than a air source heat pump. Please keep us updated on how your installation turns out and the overall performance of the system.

Below is a link explaining the tax credit.

Here is a link that might be useful: Geothermal IRS tax credit guidance