thanks for the questions!!! thanks alot!!
That is one of the things that worries me about the Hybrid. One of the plumbers just saw it yesterday... the other guy is the one that brought it to my attention in the first place.
we have copper piping, not sure what the water temp is in the winter.
I will pose some of these ?'s to them and see what they have to say.
I know that these units are relatively new and that there may be some draw backs...OH what to do....
Your average incoming water temp will be pretty close to the deep well groundwater temp, but may be as much as 5-6F below that temp at it's coldest. For a rough guess, find yourself on the map, subtract 5F:
Drainwater heat recovery systems are stupid-on-a-stick devices to install and maintain. (They're ZERO maintainance!) EFI is the distributor for
PowerPipe and their warehouse is close by you in WI. Retherm and most others will sell direct. To do a price/performance anlysis, Natural Resources Canada has them 3rd party tested to a standard an maintains a model & performance list
here.
If you're a long-showering family you'll get a far better ROI with drainwater heat recovery than going with a condensing tank, and the showering time capacity approaches infinity with a standard tank + 50%+ recovery at standard single shower flows. If you're willing to spring an extra $900 to go for a HW heater that only scores a 0.86 on an EF test (barely more than a bottom-of-the-line 0.82 tankless) I can't imagine NOT also going for the drainwater heat recovery for similar money, unless there is some installation obstacle, since it can bring the as-used effective EF to over 1.0 (more than 100% efficiency) by not throwing those BTUs literally down the drain during showers, which is likely by far the lion's share of your hot water volume. Most homes with a full basement can accomodate a 4" x 4-foot in-line vertical heat exchanger. Many can handle 6-footers. The installation cost of small vs. large units are pretty much the same, only the incremental cost of the heat exchanger itself increases with size, but the increased efficiency of going larger is cost effective in a net-present-value analysis. (Basically, buy the biggest-fattest version that fits to get the best payback.)
Any decent plumber can install these- the key is to get them as perfectly vertical as possible, and to plumb the output of the heat exchanger to both the cold side of the shower as well as the cold feed to the water heater (any water heater). When you do that instead of mixing 40-45F water with the water heater's output to make nice 105F water at the showerhead you're mixing in 70-75F water, which means you have lower flow out of the water heater. And instead of the water heater having to heat the water from 40-45F to 120-140F (or whatever you've set the water heater to), it now has to only raise the temp from 70-75F. The net result is that at ~2gpm a 35kbtu 80% efficiency burner (typical standard tank size/efficiency) pretty much keeps up with a 105F shower, and you burn only about
half the fuel, and have a very short recovery time should combined laundry/dishwashing/other flows + shower actually draws down the stored heat in the tank to below showering temp. You can run back-to-back 20 minute showers all day long even with 30 gallon tank- the tank only needs to be big enough to fill your tubs.
During showers the condensing hybrid will also keep up with the flow, but will be burning at ~98% steady-state efficiency compared to a standard tank's ~80%. With drainwater heat recovery that 80% burner is getting an effective ~120% efficiency- well above what a condensing heater alone can deliver. But since it only delivers that performance during simulatneous shower & drain flows, the average as-used efficiency depends on the fraction shower-flows are of the total volume used. With Energy Star appliances and 4 showering people the water for showers will usually be well over half the total. The rest of the efficiency game is managing the standby losses (insulating the pipes, etc.)
But if you can heat water with the heating system boiler using an indirect tank you'd usually be using comparable annual fuel for hot water as going with the condensing hybrid (probably less in your case, if combined with drainwater heat recovery.)