If 1 water heater blanket is good, how about 2?

[Toddo97]

I've been reading that water heater blankets are good for saving on heating bills so I went to Home Depot today and picked one up. It was only $20 and has an insulation rating of R19 (my architect wife said that's pretty good), but it's pretty thin. Will I see any benefit on picking up another one and doubling up?

 

[EagleKeeper]

Probably not. The intention of the blanket is to reduce the outside air temp influence on the heater.

Unless the heater is outside where there is a large temperature difference a second blanket could be considered a waster of $$$.

You can put piping blankets/jackets around any exposed pipes to assist in energy conservation.

 

[Eli]

It definately isn't going to hurt anything.

 

[Thump553]

I had a conversation with a plumber who said those blankets are one of the best things for his business. Apparently they trap moisture causing the jacket to rust out much faster.

 

[HomeBrewerDude]

you will not recoup the extra $20 for the second blanket. , besides, they are designed for specific diameters, and the second one would have to be larger than the first.

 

[dullard]

There is an easy way to tell. Put on the first. Wait a day. Go feel the outside of the insulation. If it is significantly hot, then you are losing energy and need more insulation. I bet it will not be hot.

Stop reading this post if you don't want to get into a math argument.

By the way, Eli, you theoretically can have too much insulation. Heat that is conducted to insulation is proportional to the insulation thickness - Thus it is proportional to the insulation outer diameter. Thus the thicker it is, the less conducted. That is a good thing. But there is a drawback as well. Thicker insulation means more surface area exposed to the atmosphere to lose heat. Surface area is proportional to the diameter squared for a cylinder. So if you double the insulation outer diameter, you cut conduction by half but quadruple the surface area to lose heat. So eventually as you add more and more insulation you will start getting worse! Obviously this isn't the case for most people (they aren't realistically ever going to put that much insulation on). But it is theoretically possible to have too much insulation...

 

[AlienCraft]

Better to spend that money on insulating the Hot water piping after it exits the heater.

 

[Shockwave]

Originally posted by: Thump553
I had a conversation with a plumber who said those blankets are one of the best things for his business. Apparently they trap moisture causing the jacket to rust out much faster.

Get unbacked insulation. It breathes.

 

[Gyrene]

Originally posted by: Toddo97
I've been reading that water heater blankets are good for saving on heating bills so I went to Home Depot today and picked one up. It was only $20 and has an insulation rating of R19 (my architect wife said that's pretty good), but it's pretty thin. Will I see any benefit on picking up another one and doubling up?

R19 is average, which is a U-value of about .043, which is about the resistance of your average 2" slab wall, IIRC. Good for a blanket. I'd be impressed with a R-rating in the mid to high 20s, but not R19.