Improving insulation to suit an Air Source Heat Pump - what are you doing?

Mine was 70C. Yes, phase 1 is the heat pump. Afterwards it was projected at 88B. I wish I could have solar but this is my roof and I’m overshadowed by the large building next door which was a pub (now a mosque). The sun is only on the back of the house in mid summer.

I have concrete floors downstairs. I can’t afford new carpets and the floors don’t feel cold.

In that case your SAP survey isn’t correct. It states that you have suspended timber floors.

Here’s a photo of one of my suspended timber floors. The floorboards have been removed to show the joists underneath and I’ve added 90mm of insulation between them. The reel of white pipe is for underfloor heating, so you can ignore that.

The reason you feel “warm as toast” (as you first wrote) is because the heat-input to your home is more than should be necessary. It’s leaking away.

Having additional insulation does not make a house feel warmer, despite what any salesman may tell you! It simply lowers the bills because you need less energy to keep the house at that set temperature.

And please remember, I’m currently looking at theoretical strategies which would cost you nothing. If I’m going to propose solutions, I need that freedom to think “outside the box”.

I like your suggestion @Transparent of using floor insulation that already has the pipework for under floor heating. If it was possible to patch in a room at a time onto my ASHP system then I’d def have the bathroom done. Do you think that’s realistic ? I now have a new little radiator in there - after the trial is over could it be ditched and the heating supply rerouted to the floor ?

Yes @juliamc - I would certainly do this a room at a time!

The alternative is to vacate the property and move all the furniture out

UFH needs water at a lower temperature than radiators. Typically water flow at 45°C will yield a temperature on top of the floor of around 23-25°C. More than that and you end up warping wood!

I have UFH below kitchen/bathroom tiles and oak floorboards which I’ve done completely by myself. So I have a very practical knowledge of what’s involved.

The common way to achieve the required 45°C is to take the feed that usually goes to radiators (70-75°C) and mix this with the water returning from the UFH pipe. There’s a standard unit which does this.

However I’d like to ask the opinion of @Rob Whitney and @hydrosam on this because something else occurs to me which would be cheaper but just as effective!

Could either of you two gentlemen please tell me the approximate temperature of the return water to your external Heat pump at the moment?

And Rob, is a Heat pump more or less efficient if that return water is cooler?

I’m sure you can both see where I’m heading with this!

The heat pump is designed to work on DT5 so answering your question is - not necessarily 

Evidence of the deltaT of 5C in the image below. My heating is on, house at 20C and leaving water temperature is 44C, return to heat pump 5C lower. 
Rads should be optimised/upsized to work at this temperature. 
 

Perfect it’s usually a case of radiator balancing to obtain the best outcome 

Thanks Rob. I’ll spend some time on that, Northern Gas didn’t. 
Im also waiting for the pipe insulation and buffer tank to be sorted which should improve things. 

Well if the water being delivered by the Heat pump to your radiators is as low as that, then it could also safely be directed into an UnderFloor Heating pipe. Even it’s a bit higher, it would require little mixing to keep it within the required range.

I had been expecting the water required by your radiators to be much hotter.