solar hot water

[Learner]

Do pipes for solar hot water ststem need insulation?

[Bloss]

Yes.

But so should all water pipes on the output side of any hot water system. Not much point having a system to heat something so that the heat is lost again before you get use it!

Depending where you are and how cold it gets in winter you should also insulate the input pipes too.

You are trying to raise the water temperature to around 40-55 degrees so the warmer the water is on the input side the less energy (even solar) is needed to get that rise. Input water temp varies, but typically is the range from 8-20 degrees so in cold climates you are trying to get a rise of more than 30 degrees and then hold it.

You also want to retain the temperature in your hot water system as much as you can to the outlets where the water is used. This is especially important because in cold climates with long pipe runs you can loose several degrees quickly (when air temp might be below zero at night or even in the day with maxima getting only to 10-12 or so).

Insulating the output side also means that the cold running time before you get water at the desired temperature is reduced.

New HW piping comes pre-insulated, but this is a bare minimum and should be added to with the thicker foam wraps. These are easy to install and very effective - joins should be sealed with black gaffer tape.

On a separate but related issue - it is a good idea to add insulation to storage tanks too whether indoors or out. This is not always possible (especially if roof mounted, but i have done them too), but can greatly improve the efficiency of the heat retention. I have sometimes built a frame around and filled with batts and I have also just wrapped R1.5 insulation blanket around the tank and made a lid for the top.

I face the aluminium side out and use aluminium A?C duct tape to seal and secure. This has lasted many years and saved dollars while improving the performance of the HW system. This can be used on gas and electric tanks, but take care that you are not comprising the safety of the system by blocking air vents etc. Access is as simple as just removing the duct tape and replacing afterwards, but most heaters this is needed only every few years.

If the unit is outdoors even building a shed or boxing it in can improve the performance significantly. Of course the colder the climate the greater the benefit, but all will get some benefit.

[bricks]

Yes,

Ideally speaking all pipes could benefit from insulation.

Hot water pipes will definately benefit from (need) insulation.

However it's only code to insulate the first meter of pipework from a storage unit.

The difference is a good tradesman doing good work and a hack. IMHO.

[bricks]

Yes.



If the unit is outdoors even building a shed or boxing it in can improve the performance significantly. Of course the colder the climate the greater the benefit, but all will get some benefit.

This is illegal in S.A unless the unit is an approved indoor model. ( why-i don't know).

[Bloss]

Funny eh - an approved indoor model will have even less insulation. Most indoor storage units will warm up their surrounds by several degrees even in quite large spaces. In cupboards or laundries they often heat sufficiently to make quite a good drying room - but that is through heat loss and poor efficiency so not the ideal way to dry clothes.

The important thing is to not compromise safety or by covering or insulating certain parts that need to not get overheated reduce the life span of the unit.

But I have been doing the extra insulation thing for more than 30 years and have no problems (not in SA though . . .).

[Mickj]

Last year I watched one of those "Home Reno" TV shows.
One particular episose they covered an Outdoor HWS with a timber structure. It looked real nice(like a miniture Cottage).

Anyway, later on in the show they revisited the house and said that they had to redo the structure because it was illegal. They eneded with a similar structure but did not fully enclose it. It was more of a screen . Still looked great though.
I can't remember where in the country it was.