How do I make my home sustainable?
“If I was going to spend $10k to improve the environmental performance of my house, where should I spend it?”
What a brilliant question from one of my readers! I’m going to attempt to answer it for you this month and give you my top 4 tips for sustainability actions you can do for your home. Investing $10K won’t just make you more comfortable and your home more efficient, it can create some really significant savings in ongoing energy costs. That’s architecture knowledge delivering a triple win! Woo!
Simon, the subscriber who put this to me, had an environmental assessment done for his house, but was disappointed. The consultant was more interested in signing him up for led light rebates than advising on effective interventions. This can happen – where you are really motivated to do the right thing, but the advice you get falls flat. So let’s do better, right now (my recommendations are general and evidence-based and need to be customised to your own particular circumstances, of course).
First, let me define the goal of “environmental performance”. In a nutshell, we’re aiming to consume less energy overall, and specifically less energy from non-renewable sources. In a retro-fit we do that in two ways. First, by reducing our demand for energy, and second, by supplying our remaining energy needs from renewable sources.
So without further ado….the top 4 things you can do to improve the environmental performance of your current home for a $10K budget are….
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.
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Seal the drafts!
Insulate!
Install solar panels (photovoltaics)! and/or
Replace your hot water system with a heat pump!
Wooo hoooooo! Yep. It’s sexy stuff.
No really. This is the gold dust. Notice what’s not on the list. Things like “replacing all your windows with double glazing” is not in the top 4. You can’t do it for $10K and the gains you make will be erased if you have a leaky or uninsulated home.
Let’s look at the logic and the science.
1.Seal the drafts!
A key purpose of a house is to contain a bubble of air at a comfortable temperature. We can then live in that bubble. So when uncontrolled outside air comes in, it just undermines the bubble! So:
If you have an older house with wall vents up high, fill them in with expanding foam.
Get the caulking gun out and seal around windows and doors.
Get door seals installed at the base of your exterior doors.
Search out other drafts by hovering an incense stick near the edges of suspect areas, especially at the edges windows and doors and architraves. If the smoke is disrupted, you have found a small air current that needs plugging up.
There are companies that specialise in draft sealing. Seek them out and get some quotes.
For a DIY approach you have to check out @jenlishfixitchicks the “Fix it Chicks” on Instagram.
And before you ask, yes, ventilation is great and part of the whole building approach to sustainability. But drafts are not ventilation. Ventilation is done intentionally, in the right conditions and seasons, by opening windows and doors.
2. Insulate!
Now that you’ve stopped the drafts, let’s insulate. Insulation is like wrapping your house in a blanket, and it’s important in warmer climates as well as cooler ones. Just as wrapping a tub of ice cream in a towel will help you get it home before it melts, insulation works both ways! Tropical Darwin and sub-tropical Brisbane still need to be insulated, and houses in Hobart require 50% more insulation than in Brisbane. (It’s all in the National Construction Code.) Now, retro-fitting insulation into walls is trickier and with a $10K budget is probably out of our scope. So, let’s focus on bang for our buck and improve the ceiling and roof space:
First take a look through the manhole and see what insulation you have.
Another way to check insulation in a ceiling by removing a downlight and poking a camera up the hole to take pictures. (Please don’t put yourself at risk around electricity or ladders if you are not confident.)
Problems to look out for are – is it old, compressed or covered in dust?; is it patchy, with holes and gaps in the coverage?; is it nonexistant??
Just 5% gap in coverage of your insulation reduces its effectiveness by approximately 50%! So fill the gaps!
Get some quotes from a reputable installer, include the photos you took.
Replace old style halogen or “GU10” recessed downlights with LEDs. Older style downlights and their transformers create more heat and require insulation to be trimmed back around them, making huge gaps. Modern LEDs produce very little heat and allow your insulation to be continuous. Consult your electrician for a win-win!
3. Install solar!
The first two interventions are about reducing demand for energy. This one is about supplying your energy needs with renewable sources.
Solar is especially effective if you work from home, or are otherwise at home during the day. Why? Because you get to use the electricity you make at the time you use it. Battery storage will blow your $10K budget, but photovoltaics are still in play. You can calculate the size of the system you might need here. If you are home to use your solar generation you can:
Put the washing machine and the dishwasher on in the middle of the day and clean with renewable electricity and for free.
Have the air conditioner on during the day to keep the home cooler, then turn it off in the evening when the sun has set and the solar load is less. (Now you’re insulated you’re are the tub of ice cream wrapped in the towel, keeping cool.)
Get off gas and cook with electricity during the day.
4. Replace your Hot Water System with a Heat Pump!
If you already have solar, or you aren’t at home during the day to use it when it is being produced, then do this instead. It’s a job for a plumber.
The science is really simple and a little bit miraculous. The mind-bending thing is that heat pumps don’t “make” heat like the element in your kettle. The “move” heat from the surrounding air. Even cold air has energy in it from the point of view of physics. We are way warmer down here than in the vacuum of space! So, a heat pump takes that energy from the surrounding air, “compresses” it, and through very clever heat exchangers puts that heat into your water.
Here's the efficiency equation - if a conventional “heat making” system uses one unit of energy to heat one unit of water, the “heat moving” heat pump uses one unit of energy to heat FOUR units of water. It’s up to four times more efficient! That’s huge!
It is an architect’s job to be across this stuff. And Architect GPs are, so we’re going to show you more in our next free Interactive Webinar at 5.30pm on 30th April, hosted by Architect GP wonder-woman, Louise O’Brien! You can register for Your Sustainable Home: Smarter, Simpler & More Affordable Design on our website or by following
Architects aren’t just about pretty drawings and gorgeous interiors (that’s the result of all the good work coming together). We have to be able to understand and integrate the technical stuff so that the science is as beautiful and functional as the building.
And for when you want one-on-one expertise, Architect GP has the Sustainable Design Workshop ready for you.
Through a process of preparation and briefing, an interactive workshop, and reporting on next steps, we show you where you can make the biggest positive environmental impact on your current home, or a new design you are developing.
Whether your budget is $1K, $10K or $100K, we will help you make the decisions needed to spend it well.
