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-   -   What's the best hot water now option for our house? (http://www.diychatroom.com/f7/whats-best-hot-water-now-option-our-house-63596/)

1655graff 02-04-2010 11:33 AM

What's the best hot water now option for our house?
 
Does anyone know of articles, studies, etc. that will help us decide between these 2 options?
1) hot water recirculation (retrofit kit for existing pipes), e.g. the Watts system at Amazon.
2) on-demand water heater(s).
I would think that the latter (#2) would require 1-2 units at each of the points of use for the water distro pipes of a house. 1 for each shower/bath tub, faucet (e.g., clothes washer) and 1 for each of the sinks. That's what we had in Japan (and Germany) back in the 1980's when we lived overseas.
On the other hand, the former (#1) could add to the overall energy use/inefficiency of the home, but would reduce the water wasted each time you turn on a shower or sink out at the furthest points on the water distro pipes. And I've even heard it can also reduce the amount of overall water heating inefficiency (but have not seen any data).

We have a 1956 single-story ranch in an 'L' shape that's built over a crawl space. It's hot water heater is a tank and is corner of the L. The kitchen is at the end of one leg, and the master bathroom is the end of the other leg so one has to turn on the hot water and wait at either/BOTH locations for the sinks, showers, etc. to get hot.
Thanks!

houseinthewoods 02-04-2010 03:07 PM

The recirculating pumps seem like a large energy waster to me. Not only the electricity for the pump, but you're turning your hot water pipes into radiators unless they are insulated all the way from the tank to the bathroom.

I've seen a bathroom motion detector wired to turn the pump on whenever anyone walks into the bathroom, and turn it off after they leave. This seems like a good alternative.

Rick

1655graff 02-04-2010 03:42 PM

Quote:

Originally Posted by houseinthewoods (Post 394690)
I've seen a bathroom motion detector wired to turn the pump on whenever anyone walks into the bathroom, and turn it off after they leave. This seems like a good alternative.

Rick

Rick,

1) I like the idea.
2) I'm sorry, but which pump is the motion detector turning on?

houseinthewoods 02-04-2010 04:20 PM

Quote:

Originally Posted by 1655graff (Post 394713)
Rick,

1) I like the idea.
2) I'm sorry, but which pump is the motion detector turning on?

Hot water recirculation has an electric pump (typically mounted on top of your water heater tank) that pushes hot water from the water heater tank towards the bathroom faucet, through a bypass valve under the sink, then back towards the water heater in the cold pipe. This means you always have hot water at the bathroom. It also means you always have warm water in the cold side.

The Watts product has a timer that keeps the pump off at night, but it would still run many hours a day. The pump doesn't draw much electricity (25 watts?), so that's not the big energy consumer. It's the heat radiating off all that pipe in your walls.

There are lots of variables in the equation. If I were to choose to install the recirc pump, it would probably just be for the convenience. We've got lots of water here in Missouri, and our energy prices are relatively cheap.

If you suffer from water shortage, it's probably a good idea. If you heat water with electricity or propane, it might not be such a good idea.

Keep in mind you'll need two bypass valves; one in the bath and one in the kitchen. You'll be pushing hot water to the end of each leg of your 'L'.

Rick

Scuba_Dave 02-04-2010 05:01 PM

Where are you located ?

1655graff 02-04-2010 06:20 PM

Quote:

Originally Posted by Scuba_Dave (Post 394768)
Where are you located ?

"East Bay" "Oakland hills" of the San Francisco Bay Area.

1655graff 02-04-2010 06:36 PM

Quote:

Originally Posted by houseinthewoods (Post 394740)
Hot water recirculation has an electric pump (typically mounted on top of your water heater tank) that pushes hot water from the water heater tank towards the bathroom faucet, through a bypass valve under the sink, then back towards the water heater in the cold pipe. This means you always have hot water at the bathroom. It also means you always have warm water in the cold side.

The Watts product has a timer that keeps the pump off at night, but it would still run many hours a day. The pump doesn't draw much electricity (25 watts?), so that's not the big energy consumer. It's the heat radiating off all that pipe in your walls.

There are lots of variables in the equation. If I were to choose to install the recirc pump, it would probably just be for the convenience. We've got lots of water here in Missouri, and our energy prices are relatively cheap.

If you suffer from water shortage, it's probably a good idea. If you heat water with electricity or propane, it might not be such a good idea.

Keep in mind you'll need two bypass valves; one in the bath and one in the kitchen. You'll be pushing hot water to the end of each leg of your 'L'.

Rick

OK, nOw I understand.

We want to conserve as much water as possible. And the water company has raised rates 2Xs over the past 3 years (about 30%+ in total), using the drought as their excuse (1st for non-compliance and then because people are not using as much as they projected for their budget). We also do not want to continue to fill pithchers in the kitchen, and do not want to stop using the master bathroom sink and shower because it takes so long to get hot water.

I was looking at the Watts because I had found and read a study (from 1999) for NYC of multi-resident, mmult-story buildings (45-80+ apartment). Their study had found dedicated returns/recircs gained a total 31% reduced energy (pump & heating) when only the timer turned it off overnight, and 23% when only lowering the temp trigger for recirc to 110F (as compared to the typical setting of 130-145F) no mater the size of the building and no matter the season. So it seemed to be including some level of energy efficiency into its design.

Scuba_Dave 02-04-2010 06:55 PM

I'm putting in a rainwater recovery system
Right now I have ~1000g capacity to be connected - (2) 275g containers were free
Once finished I will setup a supply for the toilets
For warmer weather/summer a solar outdoor shower will go in
Icmay also tap into this & run radiators into the house for Spring/Fall heating
We get billed for water used, then billed again for Town sewer for a percentage of that water they figure goes down the drain
Rest will be used to water gardens, top off the pool, change water in the hot tub

If sunny area is available solar hot water might be a good alternative

Alan 02-05-2010 01:26 AM

Typical practice for recirc systems are to insulate the pipes anyway. We do this on every recirc system. As mentioned above, the energy consumption of one of those pumps is almost nil. You can buy timers for them to keep them off at night. I don't particularly like the watts comfort system because it dumps the hot back into the cold, so now instead of having cold water in your hot side from sitting too long, you have warmish water in your cold side from the recirculating pump. Depending on the layout and size of your house, it could be real easy for a plumber to retrofit a recirc line using pex piping and adapters. Might be worth getting a quote.

Edit : Recirc system will not work with a tankless type water heater unless you install a storage tank somewhere in the system.

ChrisDIY 02-05-2010 09:43 AM

Easy solution
 
Get the TACO recirculation system. Simply installs on the supplies to the faucet farthest end away from heater. It turns on by motion or when you push a switch. It pumps the water from the hot side into the cold side until the hot water is sensed. Then shuts off. This wastes no water. You would buy the add on motion sensor.

http://www.taco-hvac.com/en/products/D%5C'MAND%AE+System/products.html?current_category=362

--Chris

EDIT: This will work with tankless water heaters, no reservoir tank needed. I would put in a Therm-X-Trol expansion tank next to water heater.

vsheetz 02-05-2010 09:40 PM

Quote:

Originally Posted by dawktah (Post 395172)
Get the TACO recirculation system. Simply installs on the supplies to the faucet farthest end away from heater. It turns on by motion or when you push a switch. It pumps the water from the hot side into the cold side until the hot water is sensed. Then shuts off. This wastes no water. You would buy the add on motion sensor.

http://www.taco-hvac.com/en/products...t_category=362

--Chris

EDIT: This will work with tankless water heaters, no reservoir tank needed. I would put in a Therm-X-Trol expansion tank next to water heater.

This system does not do anything for the problem of it taking a long time to get hot water to a remote fauset though, or does it?

vsheetz 02-05-2010 09:46 PM

How about a whole house gas tankless water heater (flow activated) - with a smaller electric tankless nearer the remote fausets (heat de-activated)?

When you turn on the fauset the near electric heater turns on for immediate heating of the water, then turns off when hot water arrives from the [more effecient] whole house heater.

No recirculating pump, associated plumbing, reduced energy, etc.

SULTINI 02-06-2010 07:36 AM

If you live in an area of the country that is warm most of the year I would definitely install a little recirc pump with a loop that has continuous that water circulation.

It's called a tempered loop most big industrial buildings, schools, laboratories have this.

It's a loop that runs the entire building with hot water so when you draw hot water anywhere in the building it is hot, no waiting.
'
Sounds like your water cost will be higher than the cost of the loop pump and electric.

ChrisDIY 02-06-2010 12:05 PM

Quote:

Originally Posted by vsheetz (Post 395478)
This system does not do anything for the problem of it taking a long time to get hot water to a remote fauset though, or does it?

Not sure about the "fast question." It addresses the wasted water mostly. The motion activated switch is a simple close contact. How long is it taking?


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