Clifford Design were contacted by Homebuilding & Renovating for some inside info the advantages of building to the Passive House standard, Alternatives to the Passive House standard and to try and dispel some of the myths that surround the standard.

Passivhaus: How to Build to This Low Energy Standard

What are the Advantages of Building to Passivhaus Standards?

There are other key advantages that come with living in a Passivhaus build, as Passivhaus consultant Alex Clifford explains:

  • The air in a Passivhaus in the UK is dryer than in a standard home due to the lower relative humidity of the pre-warmed air coming through the MVHR system. This eliminates the chance of mould growth and condensation on the inside of windows and has the added advantage of drying clothes very quickly when hung up inside.”
  • The air quality within a Passivhaus is cleaner and healthier, with constant fresh, filtered air pre-warmed in a heat exchanger using damp warm extract air from kitchens and bathrooms.
  • Lower energy bills and lower carbon emissions due to very low heating and cooling requirements.
  • Warm, snug rooms at a constant temperature without any draughts or cold spots in winter, and cooler rooms in summer. Floor space right up to full height windows can be used year round as there is no chill off the triple glazing.
  • Low maintenance costs as there is no need for complicated heating/ cooling with hi-tech controls.
  • Peace and quiet when the windows are shut. Triple glazed windows and thick insulation are excellent at keeping the noise out.

Is Passivhaus Certification Worth it?

The advantages of opting for a certified Passivhaus are to do with getting a measure of quality control. The design is checked over to see if it really meets Passivhaus standards, and the house is tested to make sure it follows the design.

Can You Open a Window in a Passivhaus?

There’s a bit of a fallacy that you shouldn’t open windows in a Passivhaus build, but think of it more as having better control over how your home is ventilated.

“During the heating season, your ventilation would be predominantly from an MVHR system that has pre-warmed fresh air from outside, but in the summer this may well be mainly from opening windows if that is what the occupants prefer,” suggest Passivhaus consultant Alex Clifford of Clifford Design. “The impact on heating cost from an open window in winter is minimal and it can be controlled, unlike leaks in a building fabric which are affected by the wind and weather.”

Windows and doors may need to be opened in summer to reduce the risk of overheating, especially on consecutively hot days, but in winter (and year round really), it’s less likely that people living in Passivhaus builds will feel the need to open windows, as the air is fresher and the temperature better controlled in the home.

What are the Low Energy Alternatives to Building to Passivhaus Standards?

With any low energy build it is important to set a target of what  ‘low energy’ or ‘green’ actually is as this gives a target for architects, builders and client to measure against.

“This may be to achieve an EPC ‘A’ rating or a % improvement over building regs,” explains Passivhaus consultant Alex Clifford. “The AECB has introduced a new standard that uses Passivhaus principles and design modelling but has less stringent targets than Passivhaus that some clients or contractors may have thought too onerous. It does not require third-party certification and instead can be certified by a Passive House consultant reducing the cost as compared to Passivhaus.”