Yes, existing buildings can be retrofitted to meet Passive House standards, although it may require significant renovations and upgrades to achieve the necessary levels of insulation and airtightness. Retrofitting can provide significant benefits in terms of energy savings and improved indoor air quality.
Retrofitting an old house to meet Passive House standards can meet many of the same requirements and standards as a new build. This means that you can have a certified energy-efficient home by taking advantage of all the eco-friendly tools employed at new builds. The question is, who developed the standards against which to measure quality or efficiency?
Germany’s Passive House Institute (PSI) sets standards for energy-efficient homes. Homes must meet certain requirements to earn a PSI certificate. By design, retrofitted homes can’t meet the same standards. So, the PSI developed standards specifically for retrofitted houses: the EnerPHit renovation certificate.
The EnerPHit certificate is a little easier to obtain than the PSI certificate, but the quality standards are still very high and include scores for the following:
A good score runs in the region of 75 – 90%, but some retrofitted builds have even gone over the 90% mark.
One of the primary benefits with almost immediate effect is a substantial improvement in your home’s environment. Ventilation is improved along with the quality of air. Temperature regulation also receives a boost; you don’t have to use thermostats which cost money and increase your carbon footprint.
A particularly useful benefit is the cost reduction in energy usage and utility bills. For example, a retrofit in Adelaide, used an energy-saving solution that included a purpose-built membrane, reinstating insulation, and using a more eco-friendly plaster. The result was a 95% saving in heating and cooling.
A retro-fitted home does have some limitations.
The foundations must still be solid, otherwise, it’s like the fool who built his house on the sand and watched it wash away in the rain. You want to be the wise man who built his house upon a rock. Your foundations must be stable to withstand local environmental factors.
The thickness of your walls also plays a role. Small rooms will get even smaller as the walls are thickened with insulation. In addition, unless you hire a company with extensive experience and a good track record retrofitting homes, there is a risk that the integrity of the external walls may be compromised.
Passive house renovation costs vary according to the size of your home, its orientation, and the extent of work required. Someone who is increasing the insulation around the entire building will pay more than someone who is just having their windows treated.
However, it depends on the project. Retrofitting a house with floor-to-ceiling windows is going to blow your budget sky-high.
Retrofitting is certainly not cheap but the good news is that it increases home’s value. How much value it adds depends on the extent of the renovation and the quality of the work. It’s important to choose your retrofitting expert wisely. Substandard work can devalue your home, but a good builder could potentially add thousands of pounds to your home’s value.
The first thing to know is that you don’t have to retrofit your home in one go, which is great because not many people have thousands of dollars just lying around to spend on one big project.
An energy audit is the best way to determine priorities. An assessment will calculate the current energy consumption and indicate which areas are most important in terms of immediate ROI.
For that, you need a professional.
A professional energy auditor considers all the factors that come into play before helping you decide where to start. Obviously, you don’t have to stick to the order. You work your way down the list as and when it best suits you.
When you feel you’ve ticked all the boxes, an accredited PSI certifier will inspect your house
In a word, yes. An existing building can be retrofitted using almost all the same techniques and materials as an energy-efficient new build. It can provide the same benefits too, with some modifications.
It’s expensive, yes, but the benefit to your family’s health and comfort while in the house is immeasurable.
