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Getting heat-pump ready: Blog 3 – The results, the reports and what next

This blog series by Sustainable St Albans trustee Catherine Ross follows her journey, figuring out how to get off gas heating and the steps to consider before getting a heat-pump in her 1930s semi-detached home. Blog 1 introduced the context, Blog 2 showed the process of heat surveying and air tightness testing. This, the final blog will share the resulting action plan along with indicative costs.

Recommendations report

The architects from AD Practice used all we had told them to provide two reports:

The full recommendations we received were:

  1. Loft insulation to be more airtight, especially around the perimeter. New insulated loft hatch to be installed with draught excluding seal. (Approx cost £500)
  2. Chimney to be sealed internally, to first floor ceiling level. Care must be taken to insulate at loft level to continue insulation wrap and to ventilate the top part of the chimney above the first floor ceiling.  (Approx cost £1,000)
  3. Insulating underneath the timber floor in the living room (Approx cost £5,000 + making good, decoration)
  4. Replace existing front door (Approx cost £2,500)
  5. Replace windows and patio doors in the rear with better performing double glazed or triple glazed windows with trickle vents. (Approx cost £12,000-£15,000)
  6. Cavity wall insulation and externally insulating the walls. (Approx cost £40,000-£50,000)

These fabric works were recommended in addition to installing the heat pump itself.  This is not for the faint-hearted. 

READ THE FULL RECOMMENDATIONS REPORT HERE  

Costs for these reports

The airtightness test was £260+VAT. The thermal imaging and the recommendation report combined were £500+VAT. 

Weighing up the recommendations: Which are worth it, for us?

Since we received the recommendations report, we’ve been working out which bits we actually plan to do, based on the cost/benefit and the environmental impact. 

Recommendation (see above)Our decision: go ahead or not?
Loft insulation and new insulated loft hatch.Yes, this is planned.  We’ve got a quote from a local builder, and will go ahead in the next few months, as part of a package of works.
Chimney to be sealed internally.Alternative implemented. We decided we still wanted to use the fireplace very occasionally, e.g. at Christmas, so we went for a much cheaper option and bought a “Chimney Balloon” and a “Chimney Sheep”. These block the draughts and are easily removable. 
Insulating underneath the timber floor in the living room Alternative implemented. We decided instead to carpet the room.  We chose a 100% natural wool carpet, to reduce the environmental impact, with a thick underlay made of recycled materials. Even with this, carpeting was half the cost of the insulation, and much less invasive to get done. Plus it’s snuggly under-foot!
Replace existing front doorYes, this is planned.  We’ve got three quotes from local firms and are weighing them up. 
Replace windows and patio doors in the rear Yes, this is planned.  We’ve got three quotes from local firms and are weighing them up. The big decision is between timber and high spec uPVC. Timber is twice the cost, so we’ll probably go with the uPVC, with a slightly heavy heart.
Cavity wall insulation and externally insulating the wallsNo, or at least not now. We decided this was simply too expensive to go with right now.  The heat loss calculations suggest the heat pump will cope OK without the walls being insulated, and we can review this after a couple of years. 
Plus, install the heat pump itselfYes, this is planned.  We’ve got a quote for a 16kW heat pump from a company called NuHeat and are arranging a date for installation (that will be our next blog!).  
In our house, the installation is made slightly more complicated by the fact that the equipment is a bit bigger than will fit in our current boiler cupboard, so it requires some minor building work to make space, which means coordinating the builder and the plumber. The architect is helping us sort this out. 
Heat pumps can sometimes require switching to larger radiators, since the water is at a lower flow temperature. However, based on the heat loss calculations, we’re hopeful we won’t need to do this after the fabric improvements above. We’ve decided to install the heat pump with our existing radiators, live through one winter, and then decide. 

We really hope our experience can be useful for other people. Once we’ve installed everything, and gone through a winter with the new heating system, we’ll write another blog to let you know how it all went!

We really hope our experience can be useful for other people. Once we’ve installed everything, and gone through a winter with the new heating system, we’ll write another blog to let you know how it all went!

3 thoughts on “Getting heat-pump ready: Blog 3 – The results, the reports and what next”

  1. FWIW we had an air tightness test result of 8.23, on a much more modern house, and we have no problems with our ASHP keeping our house warm efficiently (Harpenden). I wouldn’t lose sleep over it. Happy to share my experience – almost entirely good.

  2. So good of you to share the detail of your experiences. Thank you.

    The finances and cost benefits are still hugely off-putting. £20,000 up front for relief from £1,500 purely heating costs per year can never look cost justified. It would be great if someone can present some rigorous analysis. I’m happy to pay more to do the ‘right’ thing environmentally, but not excessively so.

    I’d also be very interested in hearing about heating ambitions. As people in Ukraine are legally required to keep thermostats below 15 centigrade, I’ve been closely monitoring ‘living at 14 degrees’ in my late Victorian house. Heating hasn’t been on at all yet (1 Nov). I’d be happy to share further, if anyone is interested.

    1. helenburridgesustainablestalbansorg

      Oh that is interesting about the Ukraine point – would you be interested in writing a blog on this experience? Do get in touch on our ‘contact us’ page if so.

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