Trying to figure out a way to warm up the water coming in off the street.

Here in NC we don’t have to deal with freezing temps as the water comes into the house but our underground temps are generally 50 most of the year.

I’m springing for a new heat pump water heater soon. I wanted to look at some Greywater heat exchangers but my problem is that it has to be mounted horizontally as I have a basement and my exit pipe is in the rafters of the basement.

That leaves me with one choice. The Eco drain. It’s the only one on the market that is mounted flat.

I’ve read mixed reviews but if I can warm up the water a few degrees before hitting the new water heater then it won’t have to work as hard and use the electric backups which are the old type resistance prongs.

I’ve insulated the lines in the basement. That did help but not much. Water coming in tonight was 62 at the cinderblocks and 64 going into the tank.

With ecodrain they claim they can raise the water temp 30% before going in. That would take some work off if the wh.

Has anyone had any experience or know if anyone? Like I said, reviews are mixed. The price of the eco Drain is $440 and I can Install it. Payback is 5 years.

Thanks

 

Do you think heat tape/cable could work, especially is you bought a good length of it- i.e. a 30 foot or 50 foot kit? There are some models that have a built in thermostat so the electricity wouldn’t run all the time.

 

I thought about it but didn't want to use any electricity to keep it hot. Not sure what the offset would be in savings. I'm a firm believer that doing little things here and there add up. My bill has slowly dropped from $200 per month to $120 and sometimes $100 just by small adjustments. Will keep researching but I did find this so I'm probably out on heat tape.

Typical heat tape burns electricity at six to nine watts per foot per hour. That means each 100 feet of heat tape operating 24/7 can translate to an added monthly cost of $41 to $62 to operate heat tape, says Eileen Wysocki, energy auditor for Holy Cross Energy.

 

Wow, that’s a high cost vs. benefit. I agree, nix the heat tape idea.

 

I’m bent on this idea. I’m going to figure it out. A tempering tank may do the trick

 

Solar. Search the web, there is lots of diy info out there.

 

I do like the batch water heater idea outside. I guess one idea is to do a an exterior tempering tank as well.

 

Heat Recovery From Compost - BioCycle

 

heat pump water heaters work by extracting heat from the air around them. Is the basement cold? that tends to decrease the efficiency of those. just thinking out loud. the other side effect is if you are trying to keep your basement warm the HP is pulling the heat out and cooling it. so there is a happy medium you need to find

 

No my basement is not heated or cooled. 75% of it is mostly underground so the earth keeps it cool year round. It has never been below about 55* and so I called AO SMITH today and asked before I purchased if their hpwh’s would operate at maximum efficiency at that temp and the tech said absolutely it would.

 

some good points to consider, especially which size unit to purchase for a cold basement with no/little available waste heat in the Winter:
Heat Pump Water Heaters in Cold Climates: Pros and Cons

I've considered a coil of copper or a tank over a drip pan in my attic for Summer use with drain backs to empty it in the Winter .

 

Im certainly no expert but I think this may be a bit misleading. The HP will work at the max efficiency possible at any given temp. The efficiency or COP will go up and down with the ambient temp...

 

You don't have the Englander in the basement?

 

I've thought about preheating the water in an uninsulated tank in the basement next to the wood stove. I think I could heat the water from 55 to maybe 75-80 pretty easy. That would make a big difference before it goes through the tankless water heater. My tankless is an EcoSmart. It will pull 112 amps on high but it will make HOT water all day long

 

Yes that was the disingenuous answer. The max efficiency at 50 degrees is not the same max efficiency at 100 degrees ambient. That was a salesman answer and not an engineer answer.

 

My personal opinion on water heaters are to not go with on demand units. I feel you are better off with a standard water heater and a recirculating line. I have yet to find an on demand water heater that has instant hot water to the farthest fixture. We don’t use hp units up hear as the cold weather doesn’t allow them to work efficiently. We do have to insulate the hot water pipes in houses now but the little thin insulation doesn’t help much on my opinion. Maybe I’m misunderstanding the question at hand

 

I'm 99% sure he's trying to pre-heat street water before it gets to his water heater, not keep the hot water hot. To save a few bucks.
Seems to me you have to be using an awful lot of hot water to make the drain recovery units actually make much of a difference.

 

Lots of good replies so thanks! I'm going to answer them all.