Reduce Your Carbon Footprint: Household Heating & Cooling

Giuseppe Gillespie


Topics this article covers:

  1. Topics this article covers:
    1. Passive Heating & Cooling
      1. Planting to Master the Elements
      2. Painting Your Home for Passive Heating
    2. Draughts
    3. Insulation
      1. Glazed Windows
      2. Insulation Grants
    4. Boilers/Water Heating
      1. Boiler Tips
      2. Tankless Water Heaters
      3. Combination Boilers
      4. Renewable Heat Sources for Central Heating
        1. Solar Water Heating
        2. Geothermal Water Heaters
        3. Wood Burning Stoves
        4. Almost Carbon-Neutral Biomass Boilers
      5. Heating Controls
    5. Radiators
    6. Air Conditioning
    7. References
    8. About the Author
    9. More of our blog posts…

This article takes a look at ways you can maximize the heating energy efficiency of your household and practical ways you can cut down on your carbon footprint. From passive heating/cooling to getting the most out of your heating appliances, let’s get down to business.

Passive Heating & Cooling

We’ve long been at the mercy of the venerable elements and the architects of old spent a great deal of time developing ways to incorporate passive heating & cooling techniques into building design from the strategic use of shade and color to maximizing the use of interior/exterior insulation.

Indeed, the ancient Greeks, Romans, and Chinese cared greatly about passive solar design when it came to constructing residential dwellings.

Aeschylus (Ancient Greek Tragedian, Playwright, and Soldier) wrote: “Only primitives & barbarians lack knowledge of houses turned to face the Winter sun.”

While Socrates (Ancient affluent Athenian hobo) said: “Now, supposing a house to have a southern aspect, sunshine during winter will steal in under the verandah, but in summer, when the sun traverses a path right over our heads, the roof will afford an agreeable shade, will it not?[1]

Traditional turf houses of Iceland

Here is an article from passipedia that looks at many different types of passive housing throughout history

Here is also an article from Selectra on passive homes in Ireland

While the widespread use of central heating solves many issues around heating your home, it also introduces a high cost in terms of negative environmental impact as the use of gas and electricity in central heating contributes to a large percentage of yearly CO2 emissions:

In Ireland, 2nd to transport, electricity generation and households are the next biggest sources of energy-related CO2 emissions. Electricity generation was responsible for 25% of energy related CO2 emissions in 2020 and fuel use in homes was responsible for 21%[2].

Of course if your house is already built and you don’t have the funds to renovate and take full advantage of passive solar heating you may be missing out, however there are still some simple steps you can take to lower your household’s carbon footprint and get the most out of your heating system.

Consider this excerpt from Energia:

“Your Building Energy Rating or BER rates your home’s energy efficiency on a scale between A and G. If you live in a new build then your home should be A rated, well insulated and not reliant on fossil fuel to heat it. However the majority of Irish housing stock is C-G rated where there is a lot you can do to improve your BER

Adding exterior insulation, switching to triple glazed windows or upgrading your heating system are just some of the ways you can reduce your home’s carbon footprint. In even better news, many of the changes will qualify for a grant and save you money on your heating bills over the winter months.[3]

Planting to Master the Elements

The strategic planting of trees (appropriately called treescaping) around your home can be of major benefit to the surrounding scenery, the environment, and more pragmatically, help slash your annual home heating bill by a considerable amount.

In addition to providing shade, “Trees and woodlands play an important role in the removal of carbon dioxide from the atmosphere. Through the biochemical process of photosynthesis carbon dioxide is taken in by trees and stored as carbon in the trunk, branches, leaves and roots.[4]

Another thing to consider is Green Roofing – this utilizes vegetation and a growing medium over a waterproofing membrane to provide rainwater absorption, insulation, and support for wildlife.

On hot days, normal roofs offer shade, but green roofs absorb the heat, whereas normal roofs heat up and then dissipate the heat. Under the green roof stays cool as the plants absorb the light and use it for their photosynthesis.

See also our Green Bee Bus Stop Project for a closer look at green roofing.

Painting Your Home for Passive Heating

Direct exposure to sunlight can cause black surfaces to be up to 40°C hotter than others, additionally, dark exteriors absorb 70-90% of solar energy[5].

Painting your home in a light color if you live in a warm climate can help dissipate heat and keep cool. Conversely, painting your home in a dark color if you live in a cold climate can help retain heat.

Also be sure to read up on 5 must know tips for environmentally friendly house painting from SG Coatings, an Australian-based painting services company.

White vs. Black body heat absorption


A Draughty Gallery

Brrr, feel that nip in the air? It may be that your home is battling against the ever-present threat of heat seepage; that is, heat loss from a *draughty opening such as a window or crack in the wall/floor material of your home.

*For those unfamiliar with the term/spelling, a draught (pronounced draft) here can be surmised as a current of unpleasantly cold air blowing through a room.

Draught-proofing is a relatively simple and cheap way to improve the heat retention and by extension the energy efficiency of your household. Draught-proofing can also help keep your home cool in the Summer by blocking out hot air from entering your home.

Identifying draughts ~ refer to this handy guide for the most common sources of draught within a home:


Your local hardware shop is sure to have a range of accoutrements available to purchase for the purposes of fissure sealing the living daylight out of your home; these include:

  • Air vent covers
  • Insulated underlays for flooring
  • Chimney balloons
  • Various compression and brush seals
  • Caulking gun and silicone sealant
Macaulay Culkin carefully caulks his draughty chimney using Macualay Culkin’s cool caulking gun.

Additionally, here’s a short video all about draught-proofing your home from life-sized Ken Doll Shura Taft who provides a neat overview:


Insulation, in the context of heating your home, is the act of layering material inside of walls and flooring or using certain materials in construction in order to retain heat and keep out external air.


Insulating the walls and flooring of your home helps keep heat out during Summer and in during Winter. This helps cut down on heating costs by reducing the usage and reliance of central heating.

Natural insulating materials require less energy cost to produce than synthetic materials. Natural insulators include: Sheep’s wool (also removes impurities from the air), hemp, cellulose, cork, wood fiber, clay, vermiculite, etc. For a breakdown of the benefits of using natural insulating material over synthetic, see this article from Energuide.

Also when purchasing insulation material, look for a high R-value; this indicates the material’s thermal resistance and a higher R-value means a higher insulating efficiency.

Glazed Windows

Upgrading your windows to double- or triple-glazing can help lower power bills by over 20%[6], reduce external noise, retain heat in colder climates and keep cool in hot climates.

Double-glazed window
Insulation Grants

Also check with your local authority for grants on insulating your home. Many local authorities offer an amount per m2 of insulation you plan to install.

See the different types of home energy grants available in Ireland here.

Boilers/Water Heating

Boilers Galore!
Boiler Tips

You should make sure to wrap your boiler in a thick, good quality 80mm lagging jacket, just make sure to follow the manufacturer’s guidelines before you fit it. This could help to save up to 30% on your water heating costs and it will pay for itself in a couple of months[7].

Boiler Lagging Jacket

You should also insulate the pipes with 2.5cm lagging. This will help prevent heat loss and increase your boiler’s efficiency.

Have your boiler serviced annually by a qualified technician. Also if it’s 10+ years old, upgrade it with a gas condensing boiler or a combination boiler for more efficiency. No matter your energy supplier, Borg Gais Energy provides boiler servicing and repair in Ireland.

Tankless Water Heaters
A quaint tankless water heater

Provide energy and cost savings as unlike traditional tank-style water heaters, which continuously use energy to maintain a hot water supply, tankless water heaters only expend energy when you turn on a hot water tap or when you’re using appliances[8].

The main benefits of tankless water heaters are:

  • Take up less space
  • Life expectancy of 20+ years
  • Long-term energy and cost savings

However they also come with some negatives:

  • High upfront cost
  • Inconsistent temperatures when multiple water outlets are in use
  • No access to hot water during a power outage
Combination Boilers

Or combi-boilers, act as both your central heating boiler and water heater in a single, neat unit. One of their benefits is that they heat water directly from the mains, rather than by heating a tank of water.

For an in-depth look at combination boilers see this article from Duffy Heating.

Renewable Heat Sources for Central Heating
A few renewables

Traditional oil- or gas-powered heating systems produce massive amounts of CO2 and accounts for most of the emissions in the residential sector. Renewable-sourced heating systems can significantly reduce or eliminate the carbon cost of heating your home and help save on your energy bills.

Solar Water Heating
A roof solar system

Particularly effective in warmer climates and the Summer months, solar water heaters convert energy from the sun into electricity that can be used to heat your home.

The initial cost of solar panel installation and setup can be quite high, but it’s a wise long-term investment. According to, the time it takes for a 3-bedroom house in Ireland with 4.1 kWh of solar panels to pay for themselves is ~7 years, or 6[9] if you avail of a Sustainable Energy Authority of Ireland (SEAI) Home Energy Grant.

You can also sell excess energy generated from solar paneling back to the electricity grid; for example, in Ireland:

The Government Microgeneration Support Scheme allows households with a registered microgeneration device to sell any excess electricity back to Ireland’s electricity grid. This payment is called a Clean Export Guarantee (CEG)[10].

Geothermal Water Heaters
Can be used both for heating & cooling

Or geothermal heat pumps, use a series of subsurface piping to harness the latent heat from the Earth and transfer it throughout your home; for cooling, the process is reversed.

The Earth is similar to a massive solar battery and geothermal heat pumps are an extremely energy-efficient way to harness this power; for every 1 unit of electricity used, the heat pump is capable of producing 4 units giving it efficiencies in the range of 500%.

Geothermal heat pumps provide a clean source of renewable energy, requiring no fuel and producing significantly lower pollution than traditional oil- or gas-powered systems.

Domestic geothermal heat pumps typically use coils of plastic piping buried ~1m underground

According to the EPA, a geothermal heating and cooling system can reduce energy consumption and corresponding emissions by more than 40 percent as compared to an air-source heat pump, and by over 70 percent as compared to standard heating and cooling equipment[11].

Similar to solar panel systems, this energy-efficient tech has a substantial upfront cost. According to Bord Gais Energy, in Ireland: Ground and water source heat pump systems should cost between €17,000 and €28,000. The average running cost of heat pumps ranges between €600 and €1000 per year[12].

Again, there are grants available from SEAI to help home owners cover costs of heat pump installation, ranging up to €4,500 for apartments and €6,500 for houses.

In Ireland, Ashgrove Renewables offer a product range of residential Geothermal Heat Pumps.

Wood Burning Stoves
Sleek & Elegant

In days gone, most households relied on fireplaces to provide a central point of heat. These were only ~10-30% heat efficient as they were localized to a single room.

Combining style and functionality, modern boiler stoves can offer up to 85% efficiency and interconnect to your home’s existing heating system:

Boiler stoves can be used to send heat to radiators and water tanks

So long as the wood comes from a sustainable source, wood burning stoves/boilers are a viable, low-emissions and cheaper alternative, or supplement, to oil- or gas-powered heating systems.

Homes with open floor plans will benefit most from stove heating
Almost Carbon-Neutral Biomass Boilers

Biomass boilers are similar to traditional oil- or gas-powered boilers, providing water and space heating for your home, however, they use sustainably-sourced materials such as wood chips or wood pellets as their fuel source.

Cross-section of a biomass boiler

A few videos here explain biomass and the environmental role biomass boilers have played:

Biomass boilers may not be 100% carbon neutral, widespread adoption can lead to massive deforestation if sustainability is neglected; conversely, it could lead to widespread reforestation if consumer reliance on hydrocarbons grow; nonetheless, they are a substantially greener solution than traditional heating systems and sit at ~ a halfway point in costs compared to heat pumps.

See also this overview of Biomass Boilers from

Heating Controls
Smart meter

In addition to the type of heating system you employ, the way in which it is used can play a significant role in its overall efficiency. The lower the temperature on your thermostat, the less you’ll pay for your heating bill and the less CO2 emissions will be released.

Hive, a wireless active heating thermostat

Smart meters, or a programmable, or an active thermostat, provide controls to fine-tune your heating system. Smart meters work with your existing boiler and allow you to:

  • Heat only when you need to, saving energy costs and reducing carbon emissions
  • Set up daily schedules for space and water heating
  • Accurately measure your heating system’s performance
  • In the case of a multi-room setup, allow you to efficiently heat individual rooms rather than the entire house
  • Many solutions offer a smartphone app for heating system control



Radiators are connected to a boiler via pipes throughout the walls and flooring of your home. Below are some tips to get the most out of your ‘rads’:

Keep radiators clear of large furniture blockage. Radiators need appropriate free space to work efficiently. Having them blocked by furniture such as couches, even partially, will reduce their space heating efficiency; it’s better for an entire room to be warm, rather than the back of your sofa!

Radiator covers, although superbly stylish, ultimately reduce the effectiveness of your radiators by closing them off

Over time, a buildup of air will accumulate inside radiators; this requires them to regularly be bled (a method of letting all the air out). To bleed most radiators you’ll likely need a radiator bleed key; available at most hardware shops for a couple of euro.

Bleeding radiators ensure you’re getting the most out of your heating system

Consider this; a radiator radiates heat in all directions, so a lot of that heat goes straight into the wall, which is great for the wall but not so great for poor, shivering you. Radiator Foil can be used to solve this problem. It acts as a reflective insulator, preventing the heat from passing into the wall and reflecting it back into the room. This is a cheap, easy-to-install, and effective way to cut down your home’s carbon emissions by increasing the efficiency of your heating system.

Using reflector foil will increase a radiator’s efficiency

To boldly go (pardon my split infinitive grammar pedagogues) one step further in radical radiator room roasting efficaciousness a strategic use of shelving can help redirect heat into the room, especially if the radiator is situated under a window.

Mmm Hmm

Air Conditioning

Air-con, con-air

Air conditioning units utilize an assortment of mechanical fans to heat, cool, and filtrate air. According to the Guardian: Air conditioners use more electricity than any other appliance in the home. They consume 10% of global electricity (together with electric fans) and leak potent planet-warming gases into the atmosphere[13].

Before deciding to implement air conditioning, be sure to make good use of passive cooling (the first topic in this article); used intelligently, this could reduce the need for air conditioning completely.

Ceiling fans are a stylish alternative to air conditioning units that use far less energy

If you do rely on the use of air conditioning here are a few tips to effectively reduce its environmental impact:

  • Seal any ducts on the unit and regularly clean/replace filters
  • Close all windows and doors of the room you want to cool; this will prevent the cool air escaping
  • Use the correct size unit for your needs; there is no reason you should use an industrial-strength air con unit to cool your kitchen
  • Use it sparingly in bursts, rather than leaving it on all day
  • Locate the unit away from radiators and other heat-generating sources


[1]: “History of passive solar building design,” Wikipedia, 20-Jun-2022. [Online]. Available: [Accessed: 09-Nov-2022].

[2]: “CO₂ emissions,” Sustainable Energy Authority Of Ireland. [Online]. Available: [Accessed: 09-Nov-2022].

[3]: “How to reduce your carbon footprint at home?,” Energia. [Online]. Available: [Accessed: 09-Nov-2022].

[4]: Pfeifer_A, “Carbon sequestration,” Forestry Focus, 31-Jan-2017. [Online]. Available: [Accessed: 09-Nov-2022].

[5]: “How does exterior color affect home temperature?,” Shoreline Painting, 26-Jun-2020. [Online]. Available: [Accessed: 09-Nov-2022].

[6]: bradnams_admin, “5 benefits of double glazing windows: Bradnam’s Windows & Doors,” Bradnams, 22-Aug-2022. [Online]. Available: [Accessed: 19-Nov-2022].

[7]: JOE_co_uk, “Quick energy tip no 3: Reducing your water heating costs,”, 01-Jun-2013. [Online]. Available: [Accessed: 19-Nov-2022].

[8]: N. Meyers, A. Palermo, Thelma, D. Michael, P. M, Robert, Angelo, K. Rose, A. Johnson, Jc, D. Degrange, D. Thomas, David, Tracy, R. Rines, M. V. Olinger, C. Heller, S. Packer, and T. Locke, “Tankless Water Heaters: 7 pros and 6 cons you should know,” Prudent Reviews, 27-Oct-2022. [Online]. Available: [Accessed: 19-Nov-2022].

[9]: H. Fox, “What feed-in tariffs mean for solar in Ireland,” Irish Tech News, 18-Jul-2022. [Online]. Available: [Accessed: 20-Nov-2022].

[10]: “Microgeneration for Homes: Electric Ireland,” Microgeneration for Homes | Electric Ireland. [Online]. Available: [Accessed: 20-Nov-2022].

[11]: “Geothermal vs. air-source heat pumps – united air temp,” UAT, 13-Jun-2022. [Online]. Available: [Accessed: 21-Nov-2022].

[12]: [Online]. Available: [Accessed: 21-Nov-2022].

[13]: “How to make Air Conditioning Less of an environmental nightmare,” The Guardian, 03-Sep-2021. [Online]. Available: [Accessed: 22-Nov-2022].

About the Author

Giuseppe Gillespie is an infrequent Irish writer often forced to write about himself in the 3rd person as he is not famous enough to merit someone else doing it for him. He has informed me (who is definitely not him) that he hopes this could change in future, as well as his fondness for ending things with a preposition, notwithstanding. For more see:

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