SuperHome Database

Royston, North Close

House Summary

John and Claire Somerville

House Type:
Victorian two storey detached

Carbon saving:
73% - SuperHomes Assessed  

Reported saving on bills:
more than 60% excluding Feed-in, over 100% including

Total invested:
£21k - (including cost of small extension)

  • Royston SH & family2
  • Royston SH fire
  • Royston SH external insulation

Measures installed:

  • Cavity Wall Insulation
  • Double Glazing
  • Draught-proofing
  • External Wall Insulation
  • Floor Insulation
  • Loft Insulation
  • Low Energy Appliances
  • Low Energy Lighting
  • Mechanical Ventilation Heat Recovery
  • Roof Insulation
  • Solar PV Panels
  • Triple Glazing
  • Water Saving Devices

Upcoming events

This SuperHome is only open by appointment/on request. To arrange a visit please contact the homeowner using the contact form below.

What visitors are saying

"Very informative and able to provide us with technical information."

"John and Claire were really informative, helpful and friendly too! We came away with lots of ideas."

"We found the visit extremely useful and enjoyable. Claire and John were enthusiastic, knowledgeable and very patient in answering our questions. We had a very rewarding visit."

Personal story:

Our last house was a rented, damp, expensive to heat and impossible to get warm so when we started house hunting being warm and comfortable was close to the top of the list.
Unfortunately, so was a good sized garden and a central location and with a limited budget we couldn’t tick all these boxes.

After a year of searching, an old victorian house with a decent garden within easy walking distance of the town and station came up under our budget. We realized that if we kept back a bit of the cash we’d planned to spend on the house for refurbishment we could end up with everything we wanted.


Cost savings are obviously important, as is the environment, but a part of the puzzle that is hard to quantify is just how important being comfortable is.

Measures installed in detail:

  • Cavity walls retrofitted with 50mm platinum polystyrene bead Cavity Wall Insulation (k=0.032).
  • Solid walls retrofitted with external insulation with 80mm Phenolic foam (k=0.022).
  • Existing UPVC double glazing, gradually replacing with triple glazed (Uw=0.8).
  • Main loft insulation – fibre-glass 250mm thickness topped up with further 100mm rockwool.
  • Second roof insulation – 50mm fibre-glass replaced with 150mm Celotex
  • Polypipe HR01LB SAP compliant rigid ducted MVHR (whole house heat recovery ventilation).
  • ‘Warm’ draft lobby (porch).
  • Cooker hood converted to re-circulating (internal) with carbon filters.
  • Extensive draft-proofing.
  • Solar PV – 16x Canadiansolar 250W panels – 4kWp with Sunnyboy transformerless inverter.
  • 4kW wood burner (78% efficient).
  • 100% Low energy lighting (CFL and LED).
  • Rainwater to soak-aways and water butts.

Please note: all rights reserved to Andrew Crowley for the family photos at the Royston SuperHome.

Benefits of work carried out:

Our home certainly feels warmer in the winter and cooler in the summer. It means that our energy bills have more than halved and when we do put the heating on the house stays warm.

The most dramatic change was in the old solid-walled bathroom (which previously had chronic condensation and resulting mould on the walls) – The combination of external insulation and improved ventilation has now made this the warmest room in the house with no sign of mould.

Favourite feature:

We should say insulation as this is the biggest energy saver, but the heat recovery ventilation system, which means the air in the house always feels ‘fresh’, without the drafts makes the house a hugely more comfortable place to live.

Project update:


We had a great time with a houseful of interested visitors on the 14th September.

We were also chuffed to be covered by the Telegraph on the 15th of September. Unfortunately the paper delayed the publication of the article by a week so it missed our open day. If you are interested drop us a message and we will let you know when we’ll next open our home.


We’ve recently:

  • Updated our boiler to a band A rated weather compensated boiler (Veissmann Vitodens 100-W).
  • Added another triple glazed window (Uw=0.9)
  • While replacing our bathroom (which had a suspended floor) we added an air tightness membrane, LED lighting and tripled the underfloor insulation to to 300mm.

Updated on 20/05/19

Common questions and answers for this SuperHome

Did you fit both external and cavity wall insulation? What about internal insulation?+

If you look at the photos of the house the cream walls are all external wall insulation which has worked really well. For the brick walls, which make up the bulk of the house, we were lucky that the bulk of the house is a cavity wall. This was unusual in the Victorian times, but after a bit of research I found out it is not unheard of. The challenge was that there was no standardized way of building cavities in that era so there was a fair effort involved in checking out the cavity to make sure there were no nasty surprises later. Here we had graphite treated polystyrene beads injected as they are the most insulating breathable insulation (that we could have injected). The ‘best’ approach to solid walls is very case specific but tends to come down to how much you like the outside of your house versus how much space you can afford to lose inside. In Victorian houses this can feel like catch 22!

In general loft insulation & draft proofing (including open chimneys) are often some of the most cost effective areas to improve. If your floors are suspended then this is also another possible area for attention.

Do you have any tips for insulating between floor joists?+

There is a pretty comprehensive guide to floor insulation on the SuperHomes site that I’d recommend. We only have a small area of suspended floor but this is similar to the drawing marked ‘Detail for insulation beneath suspended wooden floor’ but using rock wool.

In answer to your question, good practice would be to have a vapour barrier (or vapour) control layer between the insulation and the room.

Personally where space is not a key constraint, I like rock/glass wool as it is breathable, won’t rot, can dry out in case of problems, good in case of fire, lasts forever, fairly cheap and doesn’t take much energy to make in the first place. The question of which insulation is ‘best’ is application/case sensitive and rather subjective so you may well get other differing opinions.

I’d recommend thinking holistically about improving the house and come up with a plan for which elements you aspire to improve. This can help you avoid having to redo work and combine any similar jobs to save money. With this in mind you may find this Energy Saving Trust tool useful.

Contact this homeowner

Assessment types

SuperHomes Assessed

A home that has been visited and assessed by us and confirmed as reaching the SuperHome standard, which demonstrates a 60% carbon saving.

Homeowner Reported

Information has been provided by the homeowner about their home and energy use prior to the installation of measures and following their installation which demonstrates a carbon saving. This information has not been verified.

Remote Assessed

The homeowner has provided information on their home including what measures have been installed which has enables an assessor working on our behalf to assess their carbon savings. This home has not been visited to verify the measures installed.


This home has not been assessed, but the homeowner has reported what measures have been installed. It may be that this home is awaiting assessment.