Low Carbon Retrofits For Even the Oldest of Homes
Last Updated: Apr 7, 2025There are dozens of television shows centered on the theme of home renovation. Flip or Flop, Property Brothers, and Fixer Upper are just three of the more popular series that reveal our collective longing to improving our homes. Most of the episodes focus on aesthetic improvements to a home. Generally, they avoid more crucial questions about making our homes more sustainable and healthy for our families and the world.
Today, it is possible to build a new home that is carbon neutral or carbon zero. These terms mean that the house produces as much or more energy than it uses. But what about existing homes? Low carbon and carbon zero retrofits focus on remodeling older homes to increase energy efficiency while producing renewable energy on-site to approach carbon neutrality.
Table of Contents
- What Are Carbon Retrofits?
- What Are the Benefits of Retrofits Over New Construction?
- What Are the Economic Benefits of Carbon Retrofits?
- What Do Carbon Retrofits Focus On?
- Energiesprong Net-Zero Retrofit Kit
- Bottom Line
What Are Carbon Retrofits?
Carbon zero homes attempt to produce as much energy as they use annually. The achievement of this goal means that there are virtually zero carbon dioxide emissions associated with the house. Carbon neutrality is a popular sustainability housing strategy in the UK and other European countries. Newly built "carbon zero" homes combine solar panels, wind turbines, and other renewable energy technologies with energy-efficient appliances and airtight construction techniques such as those employed by passive houses.
Carbon retrofits adapt the theory behind carbon zero new home construction to existing homes. Carbon retrofit companies and products attempt to increase the renewable energy produced by a home drastically. Simultaneously, they aim to lower the energy demand by increasing the home's energy efficiency.
What Are the Economic Benefits of Carbon Retrofits?
A newly built carbon zero home costs between 5 and 15% more than homes built to minimum code. However, the savings from reduced heating, cooling and electricity needs offset these costs. For example, the average household in the US uses around 900 kWh of electricity each month. This consumption amounts to about $110 per month (depending on your cost per kilowatt-hour). During the winter months, suppose an average of $600 is also spent on heating with propane, natural gas, or other fossil fuels. This energy use comes out to almost $2,000 per year on utilities. Carbon zero homes can almost entirely reduce that cost through passive house design, implementation of renewable energy technology, and other energy efficiency measures.
As an added benefit, investing in low carbon or zero carbon retrofit will most likely increase your home's value. Many homeowners can also apply for a home equity line of credit to finance a zero-carbon retrofit. They could see an immediate return on investment through the monthly savings on their electricity and gas bills.
What Do Carbon Retrofits Focus On?
While each carbon retrofit will be different for each home's specific context, most carbon retrofits focus on four main areas:
- Airtightness and insulation
- HVAC systems
- Appliances and lighting
- Renewable energy
Each of these areas of focus is expanded on below.
Airtight and Well Insulated
First, a carbon retrofit aims to make the home airtight by sealing windows, doors, and other drafty areas. This objective also increases the home's insulating properties in critical areas such as the attic while also investing in energy-efficient windows. This work can be a significant investment - in the range of $20,000 investment for an average-sized home. This estimate depends on how extensive the insulating work is, the type of insulation you choose, and the number of windows that need to be replaced.
Efficient HVAC Systems
Replacing the mechanical systems that heat, cool, and ventilate your home can go a long way to reduce your carbon footprint. This strategy often includes installing an electric heat pump system and a heat or energy recovery ventilator (HRV/ERV). These upgrades could cost you around $15,000.
Efficient Appliances and Lighting
Third, zero-carbon retrofits focus on improving the overall energy efficiency of your home. You might have to get rid of that old refrigerator and invest in a newer model and also switch out your lights for LEDs. Depending on the age of your appliances and other electric devices, you might spend another $5,000 on these upgrades.
Tobias Roberts
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.
