Improving The Efficiency Of Your Home, Series 2, Heating, Cooling, (Hot) Water

One way to slow the progress of climate change is to reduce your personal carbon consumption. While we cannot efficiently make our path to carbon neutrality, we can buy ourselves time by slowing down carbon emissions and saving, as negawatt is often the cheapest form of clean energy available (and the least polluting). Also, if you have less energy to replace it is cheaper (i.e. if you cut your energy consumption in half, only half the renewable energy is needed to make it sustainable).

Our houses can look like a monolithic unit – they need heating and / or cooling, they use water and heated hot water, they use electricity and they need lighting and plumbing. But the structure and our actions can change the production of carbon by several orders of magnitude. Two houses of equal value, which are standing next to each other, can show 5 to 20 times the difference in the carbon pollution that arises in daily operation. A leaky house over 100 years old with inefficient equipment and high power consumption that generates dozens of tons of CO2 annually can stand next to a Passive House or Net Zero house that emits very little or no CO2. And there is a huge continuum between these extremes. Many existing homes that are inefficient can be upgraded to varying degrees to reduce their carbon footprint.

This will be a four part series:
Series one: insulation and airtightness
Series two: heating / cooling and (hot) water
Series Three: Connector Loads
Series 4: Building for Net Zero or Better

The standard disclaimers apply. All advice is provided for informational purposes only. CleanTechnica is not liable for damage caused by inaccurate information any Changes to your home, all information can change as our knowledge advances, and the coffee can be hot.

This series of articles focuses on single-family and semi-detached houses, but many of the concepts apply to all building types.

Solar hot water: These devices collect solar heat and use it to heat your water. These are usually very expensive to purchase and install, durable and technically very efficient.

Solar hot water has a long history and is only available in tank form. The solar heated water is often heated by the sun and then fed to one of the water heating systems previously mentioned to heat it completely, or sometimes it means two or more tanks are involved. This can save 0-100% on heating costs as using hot water during the day or evening may not require secondary heating at all, but the overnight stay may be cool enough to require warm-up for morning showers. The changing economics of solar hot water has led to analyzes suggesting that solar modules and a heat pump tank are cheaper due to the decline in the price of photovoltaic modules over the past decade. The daily amount and temperature of the hot water produced also varies depending on the day and time of year, with summer providing the highest performance and winter the lowest.

If you are considering solar hot water, include the numbers for both types as prices vary by region. Find an expert who can compare traditional solar hot water to solar panel / heat pump water heater.

An exception to the poor economics of traditional solar hot water are solar water heaters for pools, which can be cheaper than natural gas pool heaters if they are a little more capricious, again depending on the intensity and number of hours of sunlight, which change throughout the year and provided you use it Not your pool in cold winters. Do the numbers.

additional information

All hot water storage tanks experience heat loss from the tank walls over time as the perfect insulator has not yet been invented. However, modern efficiency standards have resulted in more efficient tanks with better insulation. Many countries conduct water heater efficiency tests and publish the results. Therefore, consult them when deciding between units when replacing your water heater. These typically measure a standardized case usage that takes into account burner efficiency and tank wall losses.

In addition, most water tanks are made of metal. It is therefore advisable to replace the anode rods regularly to ensure a long service life. This will prevent the tank from rusting and eventually leaking. You can consult the instruction manual or contact the manufacturer to see how often they recommend replacing the anode.

The temperature at which you heat the water also affects its efficiency. Thanks to the laws of thermodynamics, the greater it is, the faster the temperature difference evens out. The lower the temperature you set the tank to (all models should have an adjustable thermostat), the less waste heat is thrown away. However, you want to use a setting of at least 60 ° C to prevent legionella bacteria which can harm people. If you are planning to upgrade to a larger tank, a higher temperature of your current tank can emulate a larger tank. However, if you only use hot water on the tap, you may be more likely to get burned if you don’t have a temperature control valve installed. However, this workaround results in more energy loss. Ideally, you should try to use the steps in the last few parts of this series to use less hot water.

Whenever possible, make sure that all of your hot water pipes are covered with an insulating pipe jacket, which can be found at most hardware stores. There are different types, although some niche types may need to be specially ordered. Try to find the packaging with the highest R value, even if you have to order it. Wrap any exposed hot water pipes (taking into account any restrictions of a ventilation duct). However, if you have buried pipes in walls, it is often not realistic to tear out drywall or plaster / battens to insulate the hidden hot water pipes. However, if you ever have the opportunity to access these pipes, you will need to retrofit the pipe jacketing.

An underrated source of water loss is water wasted by turning on the tap and waiting for the water to warm up. This often measures 1-10 liters (0.25-2.5 gallons) each time you turn on the faucet to get hot water, depending on how far the faucet is from the hot water tank, the further away and the thicker it is the supply line is More water is wasted. You can measure how much water you lose each time you do this with a measuring cup or small bucket. Every tap in your home has a different volume of loss. So measure them all. You can try to reduce this waste by reducing the frequency with which you request hot water every day, and you can also try to find uses for the wasted water, such as: B. Watering plants, soaking saucepans, and filling humidifiers that you are using anyway. and so on. Drinking this water may not be advisable as there are many metals in your tank that are not found in cold water.

When using hot water, keep the pipes between the tank and the faucet full of heated water. For example, let’s say you run 2 L (0.5 g) of water to get warm water – 2 L (0.5 g) to wash your hands. As a result, 2 l (0.5 g) of heated water are now left in the pipes between the tap and the hot water tank. This means that 6 L (1.5 g) of water was heated for 2 L (0.5 g) of water. Extremely inefficient. There is no practical way to prevent this litter, although it will warm your home slightly in the colder months. You can wrap the pipes in foam, which will keep the water warm for a while. Hopefully, when the next hot water puff is coming soon, you won’t have to wait for the hot water to go to waste.

There are hot water circulation pumps that keep the water in the pipes hot at all times. However, this can be an incredible waste of energy as they are often heating the same water over and over and over and over again. 24/7 / 365.25. They are best avoided unless you can install a model that will only circulate the water once when you turn on the faucet.

Finally, a very small auxiliary tank on the tap is an option. This eliminates the need to wait for hot water waste, but not the rest of the tank to the tap. These are usually only electrical, which is relatively expensive and often requires additional wiring, not to mention the space that the auxiliary tank takes up.

The best ways to minimize these energy losses are to reduce the frequency of hot water demand, combine uses where possible, and use shorter run times when replacing a tank. Sometimes there is a better tank location that provides a shorter route to frequently used faucets. It may also be possible to use smaller diameter hot water supply pipes, although access to pipes inside walls is often prohibitive.

In summary, everything mentioned in this series of articles is a starting point. Although every attempt has been made to ensure the correctness and completeness of the information provided, this cannot be guaranteed. So don’t consider any of these as gospel, but as background knowledge for speaking to professionals who you should consult to analyze and recommend upgrades for your home.

In most countries there are resources available to assist you in this endeavor and there are plenty of low hanging fruits to achieve highly efficient heating, cooling and (hot) water.

Read the entire series:

First part – oil and propane heating
Part two – natural gas and wood heating
Third part – geothermal and electrical heat
Fourth part – air conditioning and geothermal cooling
Part Five – HVAC Efficiency Considerations
Part 6 – water protection – bathing, eating, dishes
Part seven – water protection – laundry, toilets and hand washing
Part 8 – Other water uses and water heaters
Part Nine – Solar Hot Water and Additional Considerations About Hot Water (this article)

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