Energy-efficiency renovation: a plan for the whole house

The best retrofits begin with an assessment of the whole building: how it is built, where heat is lost, how damp and ventilation behave, how people use it, and what the EPC says. From that comes a sequence of measures, sometimes spread over years, so that each job prepares for the next. Insulation and airtightness usually come before a new heating system, because they reduce the size and running cost of whatever heats the house afterwards.

In the industry standard for retrofit, PAS 2035, which applies to work funded through schemes such as ECO4, a retrofit assessor surveys the home and a retrofit coordinator designs and oversees the measures. Even when you pay privately, asking for someone in those roles is a good way to get a plan rather than a sales pitch for a single product.

Source: knowledge.bsigroup.com

Loft insulation, cavity wall insulation and draught-proofing are the classic first steps where they are missing. Floors over ventilated voids, solid walls and windows follow, and are more expensive and more disruptive. Each of them changes how moisture moves in the house.

As a house becomes more airtight, ventilation has to be designed rather than left to chance. Extract fans in kitchens and bathrooms, trickle vents in windows, or a whole-house ventilation system keep humidity down. Skipping this is one of the most common causes of condensation and mould after a retrofit.

Only then is it time for the heating system: a heat pump sized on the new, lower heat loss, better controls, and possibly solar panels or a battery. A heat pump survey done before insulation work can oversize the system.

Most Victorian and Edwardian houses have solid walls rather than cavity walls. They can be insulated inside or out, but the materials and details must let the wall dry, or damp and decay follow. External wall insulation changes the look of the house, so while insulation normally needs no planning permission where the appearance does not change, external insulation may, and listed buildings and conservation areas need early contact with the council.

The government has consulted on reforming consumer protection for home upgrades after evidence of failings in ECO4 and the Great British Insulation Scheme. For you, that means asking pointed questions: who designed the detailing at windows, eaves and floors, who checks the work, and what happens if damp appears.

An EPC is often the yardstick, especially for landlords. In England and Wales, domestic private rented properties covered by the minimum energy efficiency standard cannot be let with a rating below E unless a valid exemption is registered. Owner-occupiers use the EPC to track improvement and for mortgage products linked to efficiency.

An EPC measures modelled running costs, not comfort or carbon exactly. A plan that aims only at a rating can choose measures that score well on paper but do little for a draughty house, so keep comfort, damp and bills in view as well.

The installation of energy-saving materials in homes, including insulation, draught stripping, heating controls, heat pumps, solar panels and batteries, is currently zero-rated for VAT, while windows and glazing are standard-rated. Lower-income households may qualify for ECO4, the Warm Homes: Local Grant in England, Home Energy Scotland in Scotland, or Nest in Wales. The Boiler Upgrade Scheme helps with heat pumps in England and Wales.

Grants have eligibility rules and installer requirements, and the order of measures sometimes follows the funding. Check before paying for any work you may later want funded.

• the assessment the plan is based on, and the EPC before and expected after
• measures in order, with reasons and the moisture strategy for each
• ventilation design alongside the insulation
• who designs details at windows, eaves, floors and junctions
• grants applied for, and what the installer must hold to claim them
• guarantees on insulation and how defects are handled

You send the request once. It is shown to retrofit and renovation businesses near you, without your name, number or email, and one business can buy it; it pays Offrano, not you. Before that business sees your details, we tell you by email who it is, with address and phone number.

No business is obliged to take the request, which is withdrawn after 21 days without a buyer, and you never have to accept a quote. Offrano checks that buyers are registered businesses, not their competence, so check TrustMark or scheme registration yourself if a grant is involved.