We are wanting to update our home heating and hot water system and are looking at various options with low maintenance and running costs. Air Source Heat Pump is one, gas system boiler is another. Both would have an unvented h/w cylinder.
We have been told that ASHP would not be cost-effective as we are on mains gas. With the gas boiler option, we could use a twin coil cylinder and add solar thermal. However, we already have Solar PV panels and I believe there is a device available (demand-side energy management system?) which will divert any available ‘free’ electricity from the Solar PV system to the immersion heater in the cylinder. I am wondering if this could be just as efficient (and cheaper?) than installing a Solar Thermal system. We would also only need a single-coil cylinder and could add more Solar PV panels to our roof rather than the Solar Thermal panels.
I would be interested in your thoughts and if you have any information on these DSEMS devices.