I installed it all and plumbed it myself - Not a really difficult job . . . . maybe 3 on a scale of 5 The collector panel was $1K, the tanks were $600 for the pair, the circulator pump was $100, the differential controller was $200 and about another $300 for copper piping, valves, flowmeter and an analog temp guage. $2200 for the total system, give or take $100. We had no hot water heater to begin with, so we would have had to spend $300 anyway, so take away the $300 and the $400 in Tax rebates and the system actually cost us $1500 - I got $300 off my federal income tax and another $100 from the state My 'break even point' is about 3 to 4 years - It would be higher if I had paid another $1500 to $2K for a professional installation We're remodeling an old farmhouse, so we've never lived here with anything but the solar heat but the tag on the side of one of the water heaters says it costs $400 per year to run - It's a very high efficiency unit with 3 inches of polyfoam insulation, so a lesser water heater would cost more to operate. $500 to $600 per year is probably an average cost for domestic water heating per year for a family of four I REALLY don't understand why there isn't a larger push from the government on solar water heating. Unlike solar electric, or hybrid cars, this technology is pretty well perfected right now and the payback is much shorter than for just about any other 'green' energy source. It can be used in most places in the United States. The outside temp isn't a big factor in how well it works . . . . it depends more on how many sunny days you have If more houses had solar domestic hot water systems, we could make a huge dent in the total energy use of the country and just think of how much less fossil fuel we would consume Don

riellebee So I'm going to rough-in some numbers: Range: 15k btu/h Fireplace: 80k btu/h Furnace: 75k btu/h (x2) = 150kbtu/h water heater 200k btu/h (x2) = 400k btu/h Total potential load: 645k btu/h - again, an estimate. You can check your furnaces if you want to be be sure. is it likely that you would have enough things on at the same time to exceed your 425k btu/h service? - Yes, it's quite likely. What happens when you exceed the capacity of the service? The gas pressure drops and the range and the gas logs will just not run at full capacity - no big deal. But the things like the furnace and water heaters will throw error codes showing low gas pressure. The water heaters are likely to have that problem anyway, because at 30' of 3/4" pipe they are only getting about enough gas to run one of those heaters full tilt (the water heaters are variable input). The meter may be 20' away, but in actual length of pipe it's probably close to 30' including elbows. I can see close to 10' of pipe in the photo. The fact that the return line for the circulation isn't warm suggests it's not working. Fix that and insulate your pipes and your immediate problem will probably go away. BTW: Insulating the pipes is not expensive or difficult. Foam pipe insulation comes in 4' sections that just snaps around the pipes and uses self adhesive strips to hold it closed. It cuts with scissors. Even if you just did the exposed pipes in the basement you would reduce a lot of heat loss. My guess is that the builder can't really fix the "over-subscribed" gas service at a reasonable cost. One solution is to use a different water heater. A hybrid tank/tankless would solve the problem. The link goes to an AO Smith Vertex 75 gal water heater 100k btu/h and is 92% efficient and vents with the PVC vent pipe you have. I'm not particularly endorsing that brand - just using it as an example. It would provide you with plenty of hot water (you could run 1 shower continuously) and would reduce your BTU load by 300k BTU/h (gas service problem AND undersized gas pipe to water heater solved). In addition, because it's a tank of hot water - along with about 6' of hot water in the pipe - your wait would be significantly reduced even without a circulation pump. It sucks for your builder because it would cost them about $3500-4000 to fix it. They could probably realize some salvage value from the tankless heaters - say $1000-1500. But If they are only out $2-3k total I'd say they should consider themselves lucky.

Scott, FWIW, whether you have an expansion tank or well tank (which you have) doesn't matter a bit as your problem has nothing to do with a pressure/expansion tank. Woodbutcher (above) describes the application of both tanks correctly, they are identical inside and only differ in size. The issue appears to be a cross-connection between the hot and cold water. Your statement "I turned off the cold water intake to the water heater and the water started running straight cold" confirms this. - Dou you have a hot water tempering valve (usually close to the water heater) that could be back feeding between the H/C? - You said you already looked for a hot water recirc system and didn't find any. - Are there zonal shutoff valves (usually not!) so that you could isolate the problem to certain areas of the house? - If you shut off supply lines under sinks does the problem stop? - Diagnosing showers and tubs can be a problem because they can be piped as a bathroom group (lavatory + toilet + shower/tub) or individually off the supplies. If the shower/tub controls have built-n stops (uncommon) you can shut them off individually behind the faceplate. - Maybe shutoff EVERY faucet and shutoff valve inside/outside the entire house. Then start opening them one at a time, maybe repeat in different sequences. Hopefully you can physically isolate where the problem is in the house.

I was brought up in a Scouting family and learned primitive camping and survival skills early in my childhood and so did my husband. But on the cusp of 70, I'm not as well-equipped to deal with things that my 20-year old body could sneeze at...we do prepare the best we can and help our older neighbors. At some point in time, if we're fortunate, someone will be helping us. We live in a very small town and have a good community police department who check in on elders living alone. We have been helping a 92-year old widow since March of 2020. She has told us she wouldn't be able to live in her home without our help. Each day she calls the non-emergency police phone number just to check in, and if they don't hear from her (or other seniors on the program) they dispatch an officer to the property for a wellness check, and there is a lockbox on their home so the officer has access to a key and doesn't have to break a door or window to comfirm their safety. Her phone died and so the police woman took it to the station to charge it for her. We took hot soup to her for dinner on Thursday night and she mentioned that she wasn't able to start her car so DH went back with a tricklecharger for her battery. Then Friday morning he went over again and she had fallen and was on the floor, but was able to get back up on her own. So we plan to keep a closer watch over her.