04 October 2019
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This is a very text-heavy post but I thought I would share our efforts to save on our energy usage in our home.
With the constantly rising costs of energy, we have always tried to use as little electricity and gas as possible in our home and installed solar systems for both electric and hot water.
In 2016 we had the roof on our home replaced and foam insulation added which has made a very big difference to the heat loss in the winter and overheating problems we had in the summer months.
We have gas-powered central heating with hot water via a cylinder and with the addition of the solar hot water system a few years ago we have been able to reduce our gas usage by around a third throughout the year. During the summer months, the solar panel heats the water cylinder to a high enough temperature for showers and so the only gas usage is for cooking.
We have experimented with various on and off-grid solar PV systems and for a few years, we tried using a pair of 125Ah 12v batteries which were charged from five 100W solar panels. This was used for low-voltage power to run our home data logger and low-voltage lighting in several of our rooms. We also had a mains inverter which ran our home lighting circuits but we soon found that even with 500 watts of solar energy coming in, this would only run the lights for a few hours before the batteries dropped to below 11 volts and the inverter would shut off.
We removed the 12V batteries and used the solar PV panels with a 600W grid tie mains inverter which feeds a small amount of power back into the household mains when the sun shines.
Lighting Savings
Our house originally had incandescent bulbs, with 500W halogen outdoor lights in the garden. We changed to compact fluorescents (CFL bulbs) when they first became available. In the past 3 years, we have replaced all the CFLs with LED lights with similar light output and we changed to using daylight colour bulbs which we find give off a much better light compared to the more orange-coloured CFLs and "warm white" LEDs.
Most rooms have bayonet fittings, but the kitchen and loft used 5ft (1500mm) fluorescent tubes and these were replaced with Philips LED tubes. When we first purchased the LED tubes, they cost around £50 each but they are now down below £10 each when purchased online!
Total Watts for all lighting
Original Incandescent bulbs: 2360W
Using CFL and fluorescent tubes: 1879W
Current LED Bulbs: 224W
Total Saving: 2136 W
Measuring the electric usage
A few months ago we purchased a HOPI meter after seeing one being used on the Bigclivedotcom youtube channel and we have been using this to measure the energy usage of different devices around the house. We compared the accuracy of the HOPI meter against our bench multimeter and it seems to be close enough for mains measurement.
Our home data logger also monitors and logs the electric meter and gas meter readings via pulse sensors so we can have a daily total of energy used. We have experienced some issues with missed pulses which we are currently trying to fix.
Computers
Our desktop machines and dual monitors have been optimised as much as possible with SSD drives replacing hard disks and high-efficiency power supplies. The monitors use around 50W each when running and this only drops to around 25W when on standby, so we have to remember to power them off at the UPS when not in use.
We tested the APC Uninterruptible Power Supply (UPS) and when it is powered down, they still use around 8 watts and so if they are left connected to the mains 24/7 they cost £9.81 per year (current electric price is 14p per KWh). By turning these off at the mains at the end of the working day we are saving about £10 each year on each computer.
Our network system comprises a network switch, firewall, Linux server, router and a small UPS which combined use 50 watts and costs us £62 per year. We have a small network attached storage server and this uses 65W when running and 0.4W when in standby mode so we now power this down to standby mode at night to save power.
TVs and Smart Speakers Standby savings
We measured the standby power from our TVs and smart speakers and sound bars and were surprised to find that when not being used they are drawing around 25W each on standby.
Our living room TV and the speaker use 24W, my TV and its soundbar use 26W and Andrews's TV uses 26W on standby which adds up to 675kW/h used each year at a cost of over £110.
As the TVs and sound systems are only used part of each day, we decided to install plug-in power timers in each room and only have the units powered on when they are likely to be used. With these savings, the standby power consumption will save us around £65 per year.
The Loft Workshop
All our mains-powered test equipment in the loft has always been plugged into separate wall sockets in the past, but we wanted to be able to switch all of the kit on and off using a single switch.
The new IEC distribution board purchased at a local radio rally a few months ago allows us to have all our mains-powered test equipment connected to a single socket.
When all the equipment is connected but left on standby the internal power supplies are drawing between 25-30 watts so being able to turn it off using a single switch, when not in use, will give us a small power saving on our electric bills.
Electric and Gas meters
Our electric and gas meters are the older "dumb" style meters with pulse outputs. We have to take the readings manually and send them to our energy providers and once or twice a year they send someone to read the meters to check we are giving them the correct numbers each time.
We are currently using e.on energy for our electric and gas supply and for the past months they keep contacting us via letters and emails asking us to get the newer smart meters.
After the latest emails from e.on, we decided to get them to install new SMETS 2 smart meters so the readings could be sent automatically and in the future use, their own API’s to be able to access live and historic usage data.
Changing from our current "dumb" meters to new "smart meters" would mean that we would lose our current gas usage monitoring as the new smart gas meters do not have a pulse output but the smart electric meters would have the flashing front LED our datalogger uses.
Smart Meter installation and failure
We booked an appointment for the engineer to come today to install the new smart meters but after he had been working on it for nearly 2 hours with the electricity turned off he found there was a problem with the network connection and the electric meter was failing to "connect to the provisioning service". This meant that he couldn’t proceed with the gas meter installation and would have to remove the smart electric meter and reinstall our old "dumb" meter!
The engineer told me that this happens from time to time and the network often drops out for hours at a time so they cannot install any new meters while it is offline. The smart meters use mobile networks to communicate and I know the corner of the house where the meter is installed is a radio blackspot also my mobile phone has very poor reception there so that may have been the problem.
We were told to contact our energy provider again to arrange for another engineer visit to try to install the meter again but after more research about problems with the current second-generation meters and network connectivity issues, we think we will stick with our older "dumb" meters and continue to use our own data logger to keep track of our energy usage.
Svein Erik Duus
Hi Brian. I find your blog/website fascinating. I have been in contact with Andrew, as I have bought a couple of things from your shop. I found this page when I randomly seached for how to wire a DS2413 with an optometrist-isolator. I am retired Norwegian living in Oslo and found the world of RPIs and small electronics a very good pastime, when I am not exercising. I am 74 and enjoy offroad biking, skiing and in general keeping an healthy lifestyle. My home/house is from 2002, and already then I decided to put a lot of money into what you can call pre-smarthouse things. It is a large house, almost 390 sq. meters. In order to save energy, it was build with 40 cm thick insulation in the roof, the walls have 25, all windows with argon gas, and the basement in 18 cm concrete, with 12 cm of styrofoam cladding. Underfloor is 40 cm of simpler foam. The heating is underfloor warm water tubes, with quick heating from an aermec 6 kw hot water convector. Hot water is from an energy well, drilled 150 m deep into the rock outside the house using an heat pump/compressor to take out as much energy as possible. Of course we have a ventilation system with heat exchange equipped with a so-called enfalti-cross flow unit.
I have been reading with great interest the things you are publishing. I am very much on the same track. My house is stacked with KNX modules, and In order to save money, I have taken several courses in ETS, the programming management of KNX. I am trying to work myself into the world of sensors and monitoring things, with the same intention as yours: to save energy and to make use of it in the most efficient manner.
My geo-heating system is probably saving me as much as 20.000 kWh a year. I am now studying ways to have it deliver even more heat, at a lower cost. The pump itself is now 17 years, and I have made a plan to replace it within 5 years time. The newer pumps are more efficient and more intelligent. Here in Norway the utility companies have installed digital readers using the 4G telephone network to read the consumption. The readers are supposed to enter into a new type of network, using the high volt internal grid, called Home Area Network, or HAN. I have ordered the HAN gate to be opened and shortly I will be able to se my consumption in real time. The price of the kWh is dependent on a energy exchange system called Norpool, and I can have my tariff on so-called spot price. So one of the considerations is to have the heat pump work heating up a larger deposit of water in the night when prices are lower, and use the heat during the day. I am not certain that the small savings in terms of costs, will match the cost of the installations.
I am also now working more on the ventilation system. I have installed 3 CO2 sensors (2 kne and 1 helios) and it seems that the air quality is extremely good, even having the ventilation off for several hours during the day. It seems like I can make considerable savings in energy by getting the system to work on demand.
As we already do 95% of our driving with an electric car, I have also started thinking of upgrade my small battery on my i3 to a larger one, purchase another similar and install a battery pack in my garage, fueled by solar power from the garage roof, and let that take care of all the electricity I need for driving ++. It is about 8.000 km a year. At 0,16 kWh pr km, that is only 1.500 NOK a year at a cost of 1,2 NOK pr kWh. I doubt I will be meet the brake-even point in my lifetime, but it could be fun to make it work.
When I read about your effort, I thought you would like me sharing this with you. It is important that each of us get our CO2 footprint down, and energy consumption is one of the areas with a lot of benefits. Using the bike is another. I will go on following your blog and if there is a chance to consult you or Andrew once in a while, I would appreciate that very much. Please feel free to ask me questions. Merry Christmas!
Brian
Hi Svein,
Thank you for your comments regarding our projects and the info about your home systems.
We would like to have an electric car but our home is a terrace house with the pavement direct outside the front door and we don't have any way to charge a car without running the cable across the public pavement.
We only drive around 3 thousand miles (4800km) each year and so an electic car would be ideal transport for us. Please contact us if you have any questions about our products on the shop or anything else.
Many thanks
Brian