Sunamp heat battery for hot water?!

davmar18

I am currently living in an all electric powered property, which at present has a large water immersion storage tank for both hot water taps/ shower and the wet central heating system. 
To be quite honest, I hate it. It seems so inefficient. I heat up the water during the E7 hours (1am-7am), and it's fine for a hot shower first thing in the morning, but by the time the evening comes it's lukewarm or even cold, because when we use the hot water, it tops itself up with cold water from the mains. Rubbish thing. 

I have looked at these Sunamp battery heaters for our hot water supply and so far they look good.

(Just for the benefit of this post, I want to ask about hot water, and not heating) 

They look quite effective, and from what I've seen, you can get them in 3kwh version, which compared to our storage heater, which is an immersion, it runs at 12kwh. Surely there can't be a comparison?! We live in a small 2 bed flat, so can't see why we'd need anything more than 3kwh. 

My electric bills for December, and January were horrible. £430 for December, and albeit better, £384 for January. I'm certain it's because of this useless but expensive immersion storage boiler. 

I think I'd save energy getting a Sunamp. But has anyone else made a similar move please? If so, can you help with how you managed? 

Reed_Richards

Are you sure you know how your hot water storage tank works?  If it supplies both central heating and hot water it is likely to be a Thermal Store.  In which case your radiators will get cooler when you hot water gets tepid.    If you get the Sunamp heat battery you will need to put it somewhere but you still need the water tank for heating, you say.  But you don't want to consider this issue.

The heat battery works by passing cold water through it, which it heats from the heat stored inside.  If 3 kWh is enough stored heat to meet your hot water needs for the day then well and good but do you know that or are you simply attracted to the nice small number?  Sunamp claim that their heat batteries are very well insulated so that may well be a better option than a poorly-insulated tank of water.  But they cost a lot more than a tank of water.

Your electricity bills are high.  If you are heating your house and your water with electricity then most of the expense will almost certainly be the heating, not the hot water.

It seems to me you are being guided by your dislike of tepid water out of the taps without any actual data on what is costing you the money.  You could be about to spend a lot of money on something that won't have much effect on your bills.           

Solarchaser

I'd be interested in more data, how big is the tank, how big is the house, how many kwh do you put into the tank every night.

Where in the tank is the draw off for hot water (assume the top) and where is the draw off for heating?

The sunamp can only heat at 2.8kw as that's the size of element it has.

70sbudgie

How old is your current system? I am wondering if it might not be more cost effective to replace the tank with a new, modern, efficient hot water tank?

Perhaps one with an integrated heat pump? (Though that would be a different price bracket and may be back to comparable with the Sunamp).

From what I have read about the Sunamp thermal stores, they currently seem like a good substitute for a combi boiler where space is at a premium - in a small flat that doesn't have space for a hot water tank or heat pump. I'm not sure if it would be the most appropriate solution for you if you already have a hot water tank?