look into the new "Condensing" Gas Water heaters. They have efficiencies well into the 90% range and claim they put out as much water as a conventional 75 Gallon water heater. AO Smith is probably the best known one , but more new ones are coming. I heard they qualify for different Govt + Gas Co incentives/rebates. We will need a new water heater soon, to replace an old conventional 50 gallon gas water heater that uses a pilot. Since our gas bill is usually less than $13 in the summer, and I'm 68 years old, I will probably buy another conventional gas water heater--we don't use that much hot water and the price of the condensings are around $500 more ($1600) v/s probably around $1000 for a good quality conventional one. Were I younger and used more hot water or had a higher gas bill, I would certainly go with the Condensing one, and it's still not "Written in stone", that I won't! HTH's Gary

Actually, the instruction manual shows connections for a different controller (not the "rf" series). If you look underneath your stove, you'll notice that there are different connectors and a different configuration, wiring, etc. After 8 years, my controller has started to fail and allows the stove to remain fully on or not to come on at all, despite the thermostat settings. I've contacted our local dealer who tells me that 1). The controller is no longer being made. 2). The complete burner unit will have to be replaced at a cost of about $400-$450 to allow for a thermostat to be wall-mounted. We're in the process of ordering the parts for that option since my wife has cancer and we cannot "chance" a stove failure.

Wow, thanks for all the good input. I didn't intend it to become a debate about solar, but found that interesting as well. I'm not familiar with the lease program that is mentioned. I'm looking to have an array installed that will be owned completely by me. I can get a 20kw system installed for about $60,000. There is a new Duke Energy program offering $1 rebate for each kw installed, so subtract $20,000. Then there are 55% state and federal tax credits, reducing the investment further to $18,000. The system should generate about $2,500 in energy per year (assuming 9 cents per kwh), resulting in about a 7 year payback. There is also potentially a benefit I can derive from depreciating the asset, but am not sure that is allowed, so need to check with my tax expert. I think the main different between now and before is the $1 Duke rebate. Without that, I agree the payback period would be too long (about 11 years), but a 7 year payback seems reasonable to me. There is always the possibility of repair costs in the first 7 years which could lengthen the period a bit, but the warranties on the panels at least are much longer than that. In any case, I think it is a worth a try. With regard to the water heater question, I agree that two heat pump units might be too many, as the one in the basement might be idle for long times, so am not considering doing 1 heat pump (for the upstairs which will get used daily, but shouldn't use more than 80 gallons per hour as there is only 1 shower), and then a gas powered tankless for the basement. We have natural gas that will be already piped to the house for the stove/grille. Any other thoughts or suggestions are welcome, thanks for the lively debate!

My Rinnai gas tankless water heater has a built in recirculation feature. My furthest bathroom is 50' from the tankless. The shower is hot within 8secs of turning it on. My recirculation pump is on a timer and is programmed based on my family behavior. I was really concerned after reading so many of the reviews online about tankless water heaters topics like temp sandwich and not being able to use multiple showers and appliances at the same time. I have low flow shower heads in my bathrooms from Grohe and Hansgrohe. Two of my bathrooms have thermostatic valves. The third has a very old pressure balance valve that will be replaced soon. The shower heads are rated at 2.5gpm. They perform really well. The tankless also has a feature to fill a bathtub,. I have used this once and the tankless worked like a champ and filled a 50gal tub in 9 mins. I have city water and will perform my first flush of the system in May. I was also afraid of the temperature drops as it got colder. We had a week of sub zero temps and I noticed no impact on the water heater. We can take two showers concurrently, run the dishwasher, washer and a faucet at the same time. My home has a crawl space and most of my plumbing runs through the crawl. The tankless unit is hanging on the wall in the utilities room. Just wanted to post another experience in tankless. One of the main drivers for going with tankless in my case was that I needed the space. The tank heater blocked access into the utility room and a wall needed to be taken down to remove the heater. I have a Rinnai RUR98i. Good luck!