Improving The Efficiency Of Your Home, Series 2: Heating, Cooling, (Hot) Water – Part Six

One of the ways to slow the advance of climate change is to reduce your personal carbon usage. While we can’t efficiency our way to climate neutrality, we can buy ourselves time by slowing the rate of carbon emissions and conservation, as Negawatts are often the cheapest form of clean energy available (and the least polluting). Also when you have less energy to replace, it’s cheaper to do so (i.e. if you cut your energy use in half, then only half the renewables are needed to make it sustainable).

Our homes can seem like a monolithic entity — they need heat and or cooling, they use water and heated hot water, they consume electricity, and need lighting and plumbing. But the structure plus our actions can alter how much carbon is produced by several orders of magnitude. Two equivalent homes standing side by side could have 5 to 20 times the difference in carbon pollution produced in daily operation. A 100+ year old leaky home with inefficient appliances and high electricity use creating dozens of tons of CO2 a year can stand next to a Passivhaus or Net Zero home, which has very low or even no carbon emissions whatsoever. And there is a huge continuum in between these extremes. Many existing homes that are inefficient can be upgraded to various degrees to reduce their carbon footprints.

This will be a four part series:
Series One: Insulation And Air Sealing
Series Two: Heating/Cooling And (Hot) Water
Series Three: Plug Loads
Series Four: Building For Net Zero Or Better

The standard disclaimers apply, all advice is for informational purposes only, CleanTechnica is not responsible for any damages caused by inaccurate information or following any information provided, consult professional expertise before making any modifications to your home, all information is subject to change as our knowledge evolves, and the coffee may be hot.

This article series is focused on detached and semi-detached homes, but many of the concepts are applicable to all building types.

Water & Hot Water

We all use water in our daily lives, from the recommended consumption of 8 glasses a day (that advice came from nowhere) to bathing, cooking, laundry, swimming pools, hot tubs, watering the lawn, and the list goes on. The only real indication of how much you’re using is the bill you get (assuming you live where the water use is metered). The potential efficiency gains can be enormous, but as always its worth figuring out where your water is going to find those efficiencies. Most meters can be read if you understand how; there are dial types, digital types, and likely even connected online types that have data split by days or even by hours.

Every time you open the faucet you’re using water (which is why you should fix leaks as soon as possible, one drop per second (0.05mL) equals 132L or 34.8 gallons/month!). Your behavior ultimately determines your bill and the environmental impact. The water you drink for hydration is typically the smallest contributor to your bill.

Showers and baths are large contributors to your aggregate water use, and these can be measured with good accuracy. Check your water meter before and after a shower or bath to determine how much water was used and multiply by the number of showers or baths a month taken by everyone in the household. Showers are even easier to measure, as most water fixtures have a rating for Liters or Gallons Per Minute (LPM/GPM) at a standardized water pressure written on them in small print, but you should run it at your preferred temperature and pressure and measure with a bucket to determine how many liters/gallons are collected in one minute to confirm the written label. Multiply by the length of your shower, which you can measure with a stopwatch or cell phone. If you are measuring more water than the rating on the fixture, then the fixture could be worn out, missing an internal flow regulator, or you might have higher than standard water pressure.

To save water, take baths less frequently and take shorter showers. Most people won’t enjoy navy showers, but every minute of water reduced will multiply your savings. If your fixture is putting out more than 2.5GPM (9.5LPM) high pressure or not, look for a replacement. There are many types available, and some give poor performance, but some work even better than higher liter-per-minute models. Check reviews and experiment if necessary to find a good replacement unit. Many people can make do with ultra low water fixtures. 1.5GPM and even 1GPM are available, and if you can manage on these then you can save even more water. Also bear in mind that different shower heads will perform very differently at the same low flow, so don’t be afraid to research and experiment.

Feel free to consider not showering daily, there are many Google results on pros and cons. However, CleanTechnica takes no responsibility for the consequences 😉

Meal preparation can be a surprisingly large user of water in certain cases. If you want to determine how much water you’re using for a meal, then a large measuring cup used to measure all uses (whether for rinsing, boiling, mixing, or other activities) can give you accurate numbers. Your kitchen faucet aerator should also have a flow rating inscribed onto it if you look carefully. Once again, test with a measuring cup and timer to confirm its accuracy. There is no average amount of water used for meal preparation and every dish will have a different volume of water use which will even vary by the cook. Once you have measured how much water it takes for a specific meal, you can look at where you can optimize its use.

However, in aggregate, meal preparation is not a large contributor to your usage, so don’t stress too much about water use for your cooking, but it can be an interesting exercise to know how much water is being used and how and if there is a large use where you can reduce or eliminate.

Dish washing is often a water intensive activity when done manually. Once again check your water meter before and after a large load of dishes to determine magnitude. 2.5GPM (9.5LPM) aerators are also a longstanding efficiency standard for kitchen faucets, but aerators rated for lower flows can work just as well and save you water. These are swappable for most faucet types without having to replace the faucet itself. A dishwasher is often the more efficient way of cleaning your dishes, as it uses far less water (especially if you have a modern energy efficient unit) and the electricity used is often more than offset in cost by the water saved. Also, electricity is much easier to make renewable than water.

Also consider the usage of your dishes, if you can optimize the number of plates, utensils, and glasses used per day, you can dish wash less frequently. Run only full dishwasher loads, and in most cases you can leave the dishes dirty for a couple days until the dishwasher is full. Pre-rinsing everything before putting it in the dishwasher is typically completely unnecessary and its effectiveness is usually psychological. If you do happen to have some foods that don’t come off in the dishwasher, only pre-rinse those. Oatmeal and peanut butter are frequent culprits, but test them anyways, as differing models of dishwashers differ in their cleaning ability, as do different dishwasher detergents (you can check reviews and cleaning test results for different detergents online).

Stay tuned until next week for Part Seven – Laundry, Toilets, and Hand Washing.