What size hot water tank?

Kierjan

We are currently building a new house approx 2.600 square feet.
On our engineers spec we have included a 300L hot water tank and the appropiate number of solar panels needed to heat a tank of this size. We have very little south facing roof space - there are two parts of the house protruding a bit (apologies I can't think of teh right word) and we will be putting solor panels on both of those. That means we will have to link 2 lots of solar panels back to the tank. Anyway, at the moment there will just be 2 of us in the house. We never questioned having the 300L tank until recently when we were one of those Building shows and somebody suggested that we won't need a 300L tank at all until we increase the population of the house:). He suggested going with a much smaller tank, just enough for maybe 2 or 3 people and reducing the amount of solar panels, then when we need to upgrade we could. I really don't know. I know we might save a bit now by having smaller tank and less solar panels, but would it be more awkward to replace the tank and add more solar panels when the house is already built. The solar panels will just be for DHW and we will also have gas heating in the house so I presume that will heat the water during the winter. I'm fairly clueless about all of this so all opinions and advice would be welcome and appreciated.
Thanks.

Fishtits

I'm far from an expert on this and only speaking from my own experience, if you build a 2,600 sq ft house, kit it out approriately during the build. There may only be two of you now but what of the future?

Or if you decide to sell? who buys a decent sized house? big family?

I've got a 200L tank in a modest 4 bed detached, properly insulated its provided for power showers over several days.

I'd go with the 300L and appropriate panels now. Upgrading is expensive.

refco

i have a 300 litre hot water tank and have 2 panels / 60 tubes on roof this gives me plenty hot water 2 adults 3 kids in house originally looked at smaller tank but found on the scale of things not a lot to be saved on reducing tank size to be honest if i had time over i would have increased tank and amount of solar so as i could use solar to part heat house as almost everyday durning the winter the solar is giving at least 30 degrees

Kierjan

Thanks.

Outkast_IRE

Put it this way , would the cost of a smaller tank now , and slightly smaller bills really counter the future cost of
1.New tank
2. draining and refilling solar
3. Draining and refilling heating
4. Any pipework modifications needed to suit new tank .

I dont think it would pay if your planning on having a family in the next few years.

What i would do is see if i could source a cylinder with 2 immersion one up high and one lower , this way you could currently only use the top one and heat only the top third of the tank.

Carlow52

Another variant on this configuration is to use a combi boiler for hot water, using the perheated water in the tank as the inout.

However u need to get a combi boiler that will take preheated water and also provide for the odd occasion that the solar will heat the water above the combi boiler intake limit.

The bigger tank will make sense here