Energy efficiency during a renovation: what to do while the building is open

A renovation is one of the few moments in a home's life when the structure is easily accessible. Walls are stripped back, floors are lifted, the loft is exposed. For a short window, energy efficiency upgrades are much less disruptive and much less expensive.

That window doesn't stay open long. Once the plaster goes back on and the new flooring is down, the same measures that would have been relatively straightforward become a major job to retrofit. So it's worth knowing, before the builders arrive, which upgrades are worth folding into your renovation.

Here's how that plays out across the three key structural elements of your home.

Walls: insulation, ventilation and electrical work

Tired of rooms that never seem to hold the right temperature? Damp forming on the back panel of your wardrobes? If you're stripping solid walls back to brick during your renovation, this is the perfect time to add internal wall insulation (IWI) before re-plastering. IWI is often avoided as one of the most disruptive insulation measures, but that's irrelevant when your walls are open already.

Alternatively, if your home's external render is failing and needs replacing, this creates an opportunity to add external wall insulation (EWI) beneath the new render. And more generally, installing EWI requires scaffolding - so if you already have it up for something else, you'll avoid having to pay for it twice. Your home will have a fresh new look, slashed energy bills and year-round comfort.

Taking off the plaster around windows and external doors? This gives you a chance to seal any draughts around the frames that were present before. They're often hidden by the plaster, but they're still there. Just remember that if you're making the building more airtight, you need controlled ventilation to prevent the buildup of moisture.

If you know you have condensation issues or bad air quality, you might benefit from ventilation units. Of course, this means drilling through external walls and running electrical wiring through them. Do it while your walls are open. It's not just about preventing damp either. In bedrooms, CO₂ levels spike overnight as you exhale air into a closed space. Levels routinely rise from an outdoor baseline of about 420ppm up to 1500-3000ppm, when below 800ppm is ideal for proper, restorative sleep.

If you're considering solar panels, battery storage, air conditioning units or a heat pump, the electrics need to run somewhere through the house. If you close the walls up, decorate, and then have to run cables through them later, you'll have to pull out units and undo some of that decoration work. Even if you're not planning to install these technologies immediately, you can still add conduits now while the walls are open, and pull the cable through later.

Floors: insulation, underfloor heating and heat pumps

Whether you're dealing with suspended or solid floors (or a mix of both), it's worth adding floor insulation when they're lifted. It's very unlikely you'll want to lift your new wooden flooring or carpet once it's down, and adding insulation at this point is a relatively small cost that will make things so much cosier in the future. Who likes having cold feet?

This is also the perfect time to consider underfloor heating (UFH), and even more so if you're considering an air-to-water heat pump now or later. Air-to-water heat pump systems need emitters with larger surface areas relative to boiler systems, as they operate at lower temperatures and transfer heat more slowly. UFH has a much larger surface area than a radiator and pairs especially well with a heat pump.

Roof: loft insulation and integrated solar panels

Lofts tend to be a neglected area of the house, but they're a big opportunity for more storage space - or sometimes living space. Insulating the loft before boarding it up, or converting it into an extra room, gives you that extra space while keeping your upstairs rooms warmer.

Meanwhile, re-roofing your home opens up options for solar panels that would be significantly more expensive otherwise. You can get solar panels integrated into the roof instead of mounted on top, which looks much nicer, and the roof can be properly designed to support the additional weight of the panels.

Plan before the builders arrive

Wherever you're opening up the external parts of your home, there's an opportunity to improve its energy performance and thermal comfort. That's why it's so important to plan ahead, before the work starts. Once you miss that window and contractors are locking in decisions on site, it becomes much harder, and much costlier, to put right later.

Not sure which upgrades are right for your renovation? Book a call today and find out how we can help you futureproof your home.