What is an energy-efficient home?
An energy-efficient home is a dwelling that, through excellent insulation, efficient systems and renewable on-site generation, has a low energy consumption. Comfort remains high while gas and electricity use — and therefore the energy bill and CO₂ emissions — are low.
Key features
An energy-efficient home combines several measures:
Building envelope
- Strong insulation — Rc-values of at least 4.7 m²K/W (roof and facade) and 3.7 (floor) for new build
- Triple or HR++ glazing — U-value ≤ 1.0 W/m²K
- Airtight construction — q;10 ≤ 0.4 dm³/s.m²
- Avoiding cold bridges — thermally broken connections
Systems
- Heat pump — air/water or ground source
- Low-temperature heating — underfloor or wall heating at ≤ 35 °C
- Balanced ventilation with heat recovery — recovers 80–90% of exhaust heat
- Solar PV — on-site electricity generation
- Solar thermal or heat-pump boiler — sustainable hot water
Smart control
- Smart thermostat — learning behaviour, geofencing
- CO₂-driven ventilation — ventilation only when needed
- Energy monitor — insight into consumption per circuit
Levels of energy efficiency
| Level | Characteristics |
|---|---|
| Energy efficient | Label A or better |
| NZEB | Meets nearly-zero-energy requirements |
| Passive house | Heating demand ≤ 15 kWh/m²/year |
| Net-zero energy | Generates as much as it uses |
| Energy-positive | Generates more than it consumes |
Applications
New construction
New construction must meet NZEB requirements and is increasingly gas-free. In practice this means a heat pump or district heating.
Existing housing
An existing home can be made energy efficient step by step:
- Insulate — roof, facade, floor, glazing
- Prepare low-temperature heating — underfloor heating, larger radiators
- Hybrid heat pump — as a transition
- Solar PV — own generation
- Fully electric — pure heat pump, gas removed
Incentives
- Investment subsidies for insulation, heat pumps, solar thermal
- Low-interest energy loans
- Local schemes
Related terms
- NZEB
- Passive house
- Net-zero energy
- Heat pump
- Energy label
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.