Replacing unvented water heater - looking for suggestions

[riazawais]

Hi all,

I have a 10+ year old OSO unvented water (immersion) heater - model: Direct 20 RD. It needs replacing in the near future and I'd like to have it replaced with an energy efficient water heater.

Can you kind and smart people please recommend any suitable replacement products that are energy efficient? (a gas boiler is not an option in my apartment).
I don't know if asking for specific product recommendations is against forum rules, so if it is, I'd still appreciate some advise as to the type of product to get.

Thanks!

 

[stem]

If you are using electricity, then when it come to efficiency, all electric water heaters using heating elements are 100% efficient. For 1kW of electricity you get 1kW of heat. So there's nothing to choose between them on that basis.

The cost will depend upon the tariff you subscribe to, so if you go for something that can store heated water in a cylinder as you do now, you can take advantage of cheaper tariffs such as 'economy 7' or 'economy 10' and heat the water up during 'off peak' times. It won't use less electricity but you will pay less for it. Probably about half price the full rate.

If you want to go beyond that a heat pump will generate more energy than it consumes, some claim up to 300% efficiency under ideal conditions, but the maximum temperature may not get high enough in very cold weather and may still need a heating element to top it up. Although I believe some companies claim this isn't necessary with the latest technology. You would have to fork out a few grand for the kit though.