How to reduce electricity bills and hot water bills to 30%
How to lower power consumption for hot water (boiler) without reducing your comfort? How to pay less without limit yourself and without major investments? It sounds impossible, but IT IS possible!
Nowadays electricity bills are the biggest item in budget of every household. The facilities and non-engagement that give us all electrical appliances for heating, cooling and hot water, lead to the purchase and use of more and more of them. Easy satisfying household needs, thanks to electrical appliances, leads to increased power consumption, respectively to higher electricity bills. More and more manufacturers create more energy-efficient appliances and systems of electric power. But of course, the newer and more efficient systems and appliances cost a lot more money.
In this material we will give you an example (option) to significantly reduce of electricity bills with a little investment.
How to reduce electricity bills without making large investments?
Electric water heaters/boilers (with electric heater) for hot water are a fairly conservative (difficulty changing) product line. Nowadays emerge alternatives for providing domestic hot water (DHW) for home, such as:
- solar hot water systems – average investment for a family of four is in the range of 3500 -4500 BGN with return on investment 7-10 years. The calculations are compared to the average monthly consumption of 100 liter water heater (boiler) 300 kW and its expression in money 50.00 BGN/ month.
- heat pump water heaters – average investment for the same family around 2000-3000 BGN. Average return on investment compared to the same 100 liter boiler is 5-6 years.
The time has come to present the decision to reduce electricity bills and it is WiFi Internet programmable thermostat BBoil. We will prove our claim with real bills, calculations and evidence. Amount of investment – 99.00 BGN – term return on investment 5-7 months. Reduce hot water bills to 30%.
Real bills before and after installation of Internet Thermostat
Average monthly electricity bill for five months for this household:
70,98+72,07+69,98+70,84+66,04=349,91 BGN/5 months ⇒ average 69.98 BGN / month
Monthly electricity bill – October – Amount: 58,76 BGN
Includes started electric heating (at least 7-8 BGN) in transitional season (before the start of central heating)
Change of average monthly electricity bill for five months for the same household:
59,34+60,85+50,16+54,25+58,76=283,36 BGN/5 months⇒ average 56,67 BGN/month
How is the reduction of entire electricity bill?
The decrease in overall electricity bill is 19,02 %:
Average monthly bill BEFORE installation of WiFi Internet thermostat BBoil = 69.98 BGN / month
Average monthly bill AFTER installation of WiFi Internet thermostat BBoil =56,67 BGN / month
Difference in money:
Difference in %:
69,98 – 69,98*х/100=56,67⇒
You may ask, why at the beginning is written reducing electricity bills and hot water bills to 30%?
Because the reduction in bill of 19.02% is on the whole amount. But we are taking action only on the part providing hot water for the household. So more correctly would be to calculate what is the reduction of the consumption of electrical energy which is needed to heat the water.
This means to compare the difference in consumption (work) of the boiler before and after the installation of Internet thermostat BBoil:
Unfortunately because it is not installed a separate electric meter or a meter the consumption of electricity before the installation of BBoil, we will take this data from an ERP in Bulgaria. The average consumption of a 3kW boiler for household is 47.36 BGN or approx. 270kW / month::
Why electricity bill decreases in stages (after BBoil), and not immediately?
Reducing the electricity bill happens in stages (little by little) due to set different programming modes of operation of the electric water heater/boiler. Or just because the main objective in the task – reducing heat loss (= energy = money). Due to this idea was set an operation mode of the boiler, which provides the necessary hot water when needed and on a predetermined degrees.
Installing Internet thermostat BBoil was in early May. The children entered into a summer mode. The working day of adults started at 10:00 am. All family woke up between 7:30 – 8:00 am. After work, school and garden the family was in parks and neighborhood gardens to 21:30 – 22: 00pm. So because of these factors, the boiler was programmed at the following mode.
The problem with this operation is that it is located only at a daily rate, i.e more expensive electricity. After analyzing the chart of work which is attached to the application on the Internet thermostat, we made changes in the work program.
To provide hot water for morning needs, the boiler worked in the hours from 03:00 to 05: 45 a.m (night tariff) at higher degrees and for evening needs from 19:00 to 22:00 pm. at lower degrees. Summertime need for high degrees of hot water is less.
The set work program of the boiler took the following form:
Information about day and night rates for electricity during year
Daily rate/tariff for electricity
Summer time: (07:00 am – 23:00 pm)
Winter time: (06:00 am – 22:00 pm)
Night rate/tariff for electricity
Summer time: (23:00 pm – 07:00 am)
Winter time: (22:00 pm – 06:00 am)
Saving money with Internet thermostat BBoil
Significant reduction in our electricity bills comes from optimal control, which provides to us WiFi Internet thermostat BBoil! Or rather, limiting heat loss (energy = money) when the electric water heater works to maintain the set temperature, but we DO NOT use water. All economists advise us not to make unnecessary expenses and to control our family budget. Assuming similar things, we just have to control the operation of the boiler. Or more precisely – when to work, how to work, how many degrees to heat and maintain the water etc. Internet thermostat BBoil gives us all of these options.
We present the actual case to reduce electricity bill with 80 liter boiler (Bulgarian)
The electrical energy for heating the water to 60 ° C in a 80 liter boiler is 4,65 kW, heating of the water from 10 ° C (inlet of the conduit) to 60 ° C we need. I.e. 3kW boiler with electric heater would warm the 80 liters of water from 10 ° C to 60 ° C for hour and a half.
How to calculate the required power for water heating:
Q = cp m dT =(4.19 kJ/kgoC) (80 kg) [(60 oC) – (10 oC)]=4.19x80x50=16760 kJ, where:
1W=1J/1s (one watt is equal to one Joule per second)⇒ 16760kJ/3600s=4,655kW/h
Our heater is 3 kW which means that it will warm the water for 1.55 hours (3kWх1,55h=4,655kW/h);
In the formula above:
Q – heat (energy) (kJ);
cp – specific heat coefficient of water (kJ/kgK);
m – mass (weight) (kg);
dT – temperature difference between hot and cold water (K)
The formula and all calculations above will help us in the theoretical proof of reducing electricity bills. Above we supported our evidences with real data (monthly bills).
Shortly average statistics:
- average hot water needs of one family are around 30-40 liters / day with a temperature at 44 ° C:
- taking a shower – 43°С;
- handwashing – 40°С;
- shaving – 45°С;
- bath – 43°С.
The formula above and these data lead to the conclusion that a family of four needs hot water about 160 liters at 44 ° C.
This means that with the heated water in our 80 liter boiler at 60 ° C and with incoming tap water at 10 ° C, we would have 117.65 liters at 44 ° C:
80+37,65=117,65l at 44°С
A little more accounts for the consumption of electric boiler 80l:
As we mentioned above, the average hot water needs of a family of four is around 160 liters at 44 ° C. As we already know that the amount of hot water at 60 ° C in our boiler and 10 ° C inlet water, we have 117.65 liters at 44 ° C, and we are looking for how many liters at 60 ° C + how many liters at 10 ° C will provide 160 liters at 44 ° C:
We know that:
if we substitute liters with X and Y because we know the degrees ⇒
We search for:
where Х+У=160 ⇒ У=160-Х
Х=108,80 l at 60°С
From the calculations, we come to the conclusion that the provision of 160 liters of hot water at 44 ° C are required 108.80 liters at 60 ° C and 51.20 liters (У=160-Х) water at 10 ° C.
With the formula for calculating the required power to heat water, we can calculate how much electrical energy we need for heating of 108.8 liters at 60 ° C:
Q = cp m dT =(4.19 kJ/kgoC) (108,8 kg) [(60 oC) – (10 oC)]⇒
I.e. to provide hot water for all needs of a family of four, 80 liter boiler has to work 2 hours and 7 minutes:
6,33kW/3kW*60min=126.6 minutes= 2 hours, 6 minutes and 36 seconds;
What is the conclusion of all calculations?
The conclusion is that a 80 liter boiler has to work 2 hours and 7 minutes a day to provide the necessary amount of hot water on a four-person household. Measured in power or money, it resulting in average monthly consumption (bill) – 32.30 BGN / month:
6,33 kW*30d*0.1754BGN/kВ=33.31 BGN/month, where:
6,33 kW – needed average daily consumption of 80 liter boiler;
With the formula for calculating the required power to heat water, we can calculate how much electrical energy we need for heating of 108,8 l at 60°С:30d – 30 days/month;
0,1754 BGN/кВ – average price of electricity in Bulgaria.
In theory, things seem to be quite so, but in practice it is not exactly the same because:
- The average monthly consumption of 3kW boiler according to one ERP is 270kW/ month, which in money is 270kW * 0,1754 BGN / kW = 47,36 BGN;
- A lot of households in Bulgaria hold their boiler permanently switched on, as they think it is more economical. We will prove that is not RIGHT;
- It is difficult to carry the programming of certain hours of the necessary degrees;
- With a simple timer you can generate a saving of electricity, but certainly not so great. Because you can set hours of work, but you can not set different operating temperatures. The different operating temperatures also generate no small reduction in your monthly bill;
- Anticipating the needs of hot water is not always the same, so we have to maintain a certain amount in periods when there is no real need for it.
What is the real electricity bill per month for unregulated 80 liter boiler?
Numbers do not lie! Various ERPs give different average monthly consumption for a 80 liter boiler with 3kW electric heater. But let’s try to calculate what it is its actual consumption::
- In theory, it should work 2 hours and 7 minutes;
- The average consumption according to ERP is three hours a day, but they do not rely the work to maintain at 60 ° C water for 24 hours;
- By using the formula for calculating the energy required to heat the water in the boiler, we can reach the conclusion that:
to raise the water temperature up to 1 ° C, the boiler will consume 93 watts of electricity:
To heat 80 liters from 10 ° C to 60 ° C degrees is needed 4,655kW. If we divide the energy of the difference in the degrees we reach to:
The average loss per hour while maintaining at 60 ° C in the boiler and an ambient temperature (air in the bathroom, for example) approx. at 20 ° C are within 1,987 ° C / hour *
From here we come to the conclusion that 21.89 hours a day we lose 1,987 ° C * 93C = 184.76 watts / hour, measured in money 0.1754 0.18476 * = 0,032BGN / hour
0,71 BGN/day*30 days=21,28 BGN/month(losses)
* Calculations and heat losses:
Heating losses we took from real data from the chart of WiFi Internet thermostat BBoil:
Indications of digital sensor of WiFi thermostat BBoil for date – 08.11.2016. All data is taken at stopped heating to take account of the loss of energy (heat) per hour.
Average loss per hour for 08.11.2016 (2.25 + 1.25 + 2.31) / 3 = 1,94 ° C / h
Indications of digital sensor of WiFi thermostat BBoil for date – 10.11.2016. All data is taken at stopped heating to take account of the loss of energy (heat) per hour.
Average loss per hour for 10.11.2016: (1,69+3,68+3,13)/3=2,83°С/h
Indications of digital sensor of WiFi thermostat BBoil for date – 13.11.2016. All data is taken at stopped heating to take account of the loss of energy (heat) per hour.
Average loss per hour for 13.11.2016: (1,69+1,12+0,75)/3=1,19°С/h
Average loss per hour based on data from the three days (08.11.2016 + 10.11.2016 + 13.11.2016)
The actual theoretically calculated account (consumption) of electricity for the water heater is:
(2,11h*3kW+21,89h*0,18476kW)*0,1754 BGN/kW*30d=54,59 BGN/month, where
2,11h*3kW– 2,11 hours-required operating time of 3 kW heater to provide hot water;
21,89h*0,18476kW – 21,89 hours registering heating losses in the amount of 0,18476kW / hour;
2,11+21,89=24 hours a day;
0,1754 BGN/kW – average price of 1 kW electricity;
30d – 30 days a month.
This account is theoretically calculated, but it is extremely close to the real electric energy bill to provide hot water needs of a household. So if we can we reduce heat loss (energy, money) to a minimum, we will have a real chance to reduce the amount of the bill for hot water by up to 39%:
54,59 BGN – theoretically calculated electricity consumption for hot water for a family of four;
21,28 BGN. -theoretical actual heating losses per month from a boiler while it is maintaining at 60 ° C and an ambient temperature is at 20 ° C
We have an ability to reduce and limit heating losses (unnecessary expenses) with the installation of WiFi Internet thermostat BBoil. Learn about what appliances and systems we can operate via Internet with BBoi. Learn about its numerous advantages and benefits.
How to reduce bills even further – Bonus tip!
If you have not yet replaced your electric bulbs with LED bulbs, do it! Do it because:
Example: Assuming that at home you have 10 light bulbs with incandescent with power (60 to 100) watts and its average usage per day is 5-6 hours, they will consume:
[(60+100)/2]*10*[(5+6)/2]*0.1754*30=23.15 BGN/month, where:
[(60+100)/2] – average power of incandescent bulb;
10 – number of bulbs in the house;
[(5+6)/2] – average hours of work per day;
0.1754 – average price of electricity;
30 – days/month.
If in the same formula we replace power bulbs with the average power of LED bulbs, we get:
[(6+10)/2]*10*[(5+6)/2]*0.1754*30=2,31 BGN /month, where:
everything else is the same, only the power of consumers (light bulbs) is about 10 times smaller.
The price of an LED bulb is approx. 4-8 BGN. An investment of approx. 60.00 BGN will be restored in approx. 3-4 months. Life of an LED bulb is 2-3 years. I.e. at least two years you can save approx. 20.00 BGN / month of electricity bills.
In money: 24m*20BGN=480,00 BGN./2 years
I wish you successfully reducing of your electricity bills. I did it, you can do it too!