Payback period for solar heated hot water

Brital

Hi guys,
I'm currently putting on an extension in a 20 odd yr old house and am wobndering what the payback period would be for installing thermal tubes to help heat the hot water cylinder.

The extension includes updating the hot water system and we will be installing a 300 litre modern cylinder. The house has 3 showers and a bath and the hot water consumption would be fairly typical of a family with 3 young kids.

I was wondering whether it would be efficient to use solar to heat the cylinder and then use the immersion element as a top up when required. The cylinder is also heated by the boiler and I recon most of the heating will come from this source over the winter and most will come from solar over the summer.

My question is, has anyone done the maths on what would be the pay back period for with or without the solar tubes? I'm assuming i could some form of grant for this and so that should be factored in.

Any help appreciated.

thanks

homer911

Brital wrote: »

Hi guys,
I'm currently putting on an extension in a 20 odd yr old house and am wobndering what the payback period would be for installing thermal tubes to help heat the hot water cylinder.

The extension includes updating the hot water system and we will be installing a 300 litre modern cylinder. The house has 3 showers and a bath and the hot water consumption would be fairly typical of a family with 3 young kids.

I was wondering whether it would be efficient to use solar to heat the cylinder and then use the immersion element as a top up when required. The cylinder is also heated by the boiler and I recon most of the heating will come from this source over the winter and most will come from solar over the summer.

My question is, has anyone done the maths on what would be the pay back period for with or without the solar tubes? I'm assuming i could some form of grant for this and so that should be factored in.

Any help appreciated.

thanks

Payback will depend on how much water is currently used, how its generated, how much will be used in the future, how much the system will cost to install and maintain etc etc

I think the general guide is 8-10 years but personally i feel if the payback is more than you would get on putting the same sum in a deposit account, then its worthwhile..

Amateurish

Brital wrote: »

Hi guys,
I'm currently putting on an extension in a 20 odd yr old house and am wobndering what the payback period would be for installing thermal tubes to help heat the hot water cylinder.

The extension includes updating the hot water system and we will be installing a 300 litre modern cylinder. The house has 3 showers and a bath and the hot water consumption would be fairly typical of a family with 3 young kids.

I was wondering whether it would be efficient to use solar to heat the cylinder and then use the immersion element as a top up when required. The cylinder is also heated by the boiler and I recon most of the heating will come from this source over the winter and most will come from solar over the summer.

My question is, has anyone done the maths on what would be the pay back period for with or without the solar tubes? I'm assuming i could some form of grant for this and so that should be factored in.

Any help appreciated.

thanks

Be wary of anyone giving you definate figures, the payback depends on how you use hot water and how you measure your costs. If kerosene doubles would you compare to the new price? Are you factoring in interest? Do you need higher temp water or lower like in underfloor?
free calculator . . http://www.retscreen.net/ang/home.php

quentingargan

Hi Brital,

A fair share of the cost of putting in solar is the cost of changing the cylinder. This will also save on your heating costs, as it is usually replacing a pretty poorly insulated model.

A computer simulation can give a reasonably accurate estimate of heat savings on the solar system itself. Will PM you details on this.

There is an €800 grant which can come off the cost of this as well.