Hot water heater stuff

Tony Raine · 11-21-08, 11:49 AM

First off, I have a "dual element" electric hot water heater. It was installed when the house was built (about 2003), so its still pretty new. I've also replaced both elements within the last year. It sits in an "outside access" room thats part of the carport (but still part of the house)

So I'm trying to get the best efficiency out of it.

I have the elements set so that when my wife and I take our showers (her first, me second) in the morning, I just start to run out of hot water when I finish. So I think I'm good there.

Since my house in on a foundation, I assume all the hot water lines run in the attic (which is easy to access, fortunately.) I hope it isn't run through the foundation. next time i'm up there i need to dig through the insulation (blow-in). Is there a type of insulation I can wrap around the hot water pipe all the way to the bathroom? the reason i ask is because the bathroom is on the opposite end of the house, so a lot of cold water has to "purge" before hot water gets to the shower head.

i've thought about a water heater "blanket", but i'm not sure it would be worth it since the heater is so new. since i now have a storage shed, i'm thinking of taking everything out of the "water heater room" and pulling off some sheetrock and see if its insulated behind the walls. maybe i can add some more and just extra-insulate the whole room (its quite small)

cmittle · 11-21-08, 12:11 PM

I insulated all of the hot water pipes in my basement with the black insulation that you can buy in 8 or 10 foot lengths at Lowe's/Home Depot. It has a slit down the side that allows you to slip it over the pipe. I'm not really sure how much it helped, but I know it couldn't have hurt and I think I only spent ~10 bucks total.

Daox · 11-21-08, 01:04 PM

I think the insulation is worth it even if the tank is new. Insulation is only so great at stopping conductive heat transfer, and the only way to combat that is to add more/thicker insulation.

If the water lines are already covered in insulation, I don't see a ton of benefit of wrapping them with pipe wrap.

cmittle · 11-21-08, 01:56 PM

Speaking of wrapping the water heater itself I've got a question. I went down (it's in our soon to be finished basement) and touched the outside of my water heater the other day and as best I can tell it is room temperature on the outside. This indicates to me that I shouldn't worry about wrapping it as I am not losing much heat (via conduction) to the room.

Am I thinking correctly on this, or are there significant radiant effects that I should be trying to overcome as well?

Maybe I'll have to get my laser temp gun and do some measurements of the tank, the wall and floor near the tank and the wall and floor ~6 feet from the tank (and maybe the rest of the basement walls/floors for comparison).

Higgy · 11-21-08, 04:15 PM

Like Cory, I wrapped all of my hot water pipes as well in the same foam. To me, if the water sits overnight, it will be cold by morning...at least in the winter. But after you use the hot water once in the morning or whatever, every time you use it afterwards the water seems already warmish and gets hot a lot quicker I find. I think it's worth it considering how cheap it was to do.

NiHaoMike · 11-21-08, 05:21 PM

Is there already a digital control installed? If not, installing one can allow the temperature to be reduced during off-peak times for some energy saving. A modern digital control can also electronically reduce the power to better regulate temperature and prolong the life of the heating elements.

knowbodies · 11-22-08, 12:18 AM

Quote:

Originally Posted by cmittle

Speaking of wrapping the water heater itself I've got a question. I went down (it's in our soon to be finished basement) and touched the outside of my water heater the other day and as best I can tell it is room temperature on the outside. This indicates to me that I shouldn't worry about wrapping it as I am not losing much heat (via conduction) to the room.

Am I thinking correctly on this, or are there significant radiant effects that I should be trying to overcome as well?

Maybe I'll have to get my laser temp gun and do some measurements of the tank, the wall and floor near the tank and the wall and floor ~6 feet from the tank (and maybe the rest of the basement walls/floors for comparison).

As a test, just put a small blanket on your water heater and see how much heat you feel underneath it after about an hour. That should give you a bit of an indicator of how quickly your water heater is losing heat. The fact that the outside of your water heater feels like it is at room temperature only tells that the outside of your water heater is in fact at about room temperature. It doesn't tell you how fast your water heater is losing heat.

AC_Hacker · 11-25-09, 12:14 PM

Don't be fooled by thinking that heat rises. Hot air does rise, but heat actually moves in all directions.

If you can safely do so, get some insulation under your water heater, there may be as much as 15% loss there.

-AC_Hacker

11-21-08, 11:49 AM	#1
Tony Raine Helper EcoRenovator Join Date: Sep 2008 Posts: 57 Thanks: 0 Thanked 0 Times in 0 Posts	Hot water heater stuff First off, I have a "dual element" electric hot water heater. It was installed when the house was built (about 2003), so its still pretty new. I've also replaced both elements within the last year. It sits in an "outside access" room thats part of the carport (but still part of the house) So I'm trying to get the best efficiency out of it. I have the elements set so that when my wife and I take our showers (her first, me second) in the morning, I just start to run out of hot water when I finish. So I think I'm good there. Since my house in on a foundation, I assume all the hot water lines run in the attic (which is easy to access, fortunately.) I hope it isn't run through the foundation. next time i'm up there i need to dig through the insulation (blow-in). Is there a type of insulation I can wrap around the hot water pipe all the way to the bathroom? the reason i ask is because the bathroom is on the opposite end of the house, so a lot of cold water has to "purge" before hot water gets to the shower head. i've thought about a water heater "blanket", but i'm not sure it would be worth it since the heater is so new. since i now have a storage shed, i'm thinking of taking everything out of the "water heater room" and pulling off some sheetrock and see if its insulated behind the walls. maybe i can add some more and just extra-insulate the whole room (its quite small)

11-21-08, 01:04 PM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I think the insulation is worth it even if the tank is new. Insulation is only so great at stopping conductive heat transfer, and the only way to combat that is to add more/thicker insulation. If the water lines are already covered in insulation, I don't see a ton of benefit of wrapping them with pipe wrap. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-21-08, 05:21 PM	#6
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	Is there already a digital control installed? If not, installing one can allow the temperature to be reduced during off-peak times for some energy saving. A modern digital control can also electronically reduce the power to better regulate temperature and prolong the life of the heating elements. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

11-25-09, 12:14 PM	#8
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 724 Times in 534 Posts	Heat Rises? Don't be fooled by thinking that heat rises. Hot air does rise, but heat actually moves in all directions. If you can safely do so, get some insulation under your water heater, there may be as much as 15% loss there. -AC_Hacker

11-21-08, 12:11 PM	#2
cmittle Helper EcoRenovator Join Date: Oct 2008 Location: Sioux Falls, SD Posts: 56 Thanks: 0 Thanked 1 Time in 1 Post	I insulated all of the hot water pipes in my basement with the black insulation that you can buy in 8 or 10 foot lengths at Lowe's/Home Depot. It has a slit down the side that allows you to slip it over the pipe. I'm not really sure how much it helped, but I know it couldn't have hurt and I think I only spent ~10 bucks total.

11-21-08, 01:56 PM	#4
cmittle Helper EcoRenovator Join Date: Oct 2008 Location: Sioux Falls, SD Posts: 56 Thanks: 0 Thanked 1 Time in 1 Post	Speaking of wrapping the water heater itself I've got a question. I went down (it's in our soon to be finished basement) and touched the outside of my water heater the other day and as best I can tell it is room temperature on the outside. This indicates to me that I shouldn't worry about wrapping it as I am not losing much heat (via conduction) to the room. Am I thinking correctly on this, or are there significant radiant effects that I should be trying to overcome as well? Maybe I'll have to get my laser temp gun and do some measurements of the tank, the wall and floor near the tank and the wall and floor ~6 feet from the tank (and maybe the rest of the basement walls/floors for comparison).

11-21-08, 04:15 PM	#5
Higgy The Gardener Join Date: Oct 2008 Location: Manitoba - Canada Posts: 492 Thanks: 17 Thanked 8 Times in 7 Posts	Like Cory, I wrapped all of my hot water pipes as well in the same foam. To me, if the water sits overnight, it will be cold by morning...at least in the winter. But after you use the hot water once in the morning or whatever, every time you use it afterwards the water seems already warmish and gets hot a lot quicker I find. I think it's worth it considering how cheap it was to do.