Reducing energy usage

I just got our electricity bill. I was a bit shocked to discover that our usage has doubled. It’s usually pretty stable, so I imagine the difference is mainly due to the room for rent. I’ve notice that people renting aren’t exactly careful with electricity usage. And electricity isn’t exactly cheap here.

I’ve already changed the bulbs in the guest room and adjoining passage from CFLs to LEDs. I’m in the process of transitioning all our lighting from CFL to LEDs, but it is a slow process.

I was also thinking about a heat pump water heater. Does anyone have experience with these? A search found me, which at Rs 46000 (USD 677 approx), is a bit on the expensive side, but affordable. Of course, it does depend how long the water heater continues to work for.

Does anyone have other ideas about reducing energy consumption? Auto shut off lights are a possibility, but I’m not sure how much difference those would make.

I bought 12x 7w led bulbs for £12 on ebay. I have 11 lights. Was cheap enough. Apart from that most people use a tablet or just their mobile phone. Plus they’re usually out all day.

My boiler is a gas powered combi boiler so hot water on demand. No tank.

What exactly are they doing. Lol

I guess the best advice would be try suggesting them places to visit so they aren’t at home so much.

Yup… This is what happens. I just got my electric bill. When my boys are off at university, my bill is between $75 and $80. Now, with one month home and all of their showers, additional laundry and dishes, etc, the bill is $140!!! I also had a guest for three weeks. MOre people in the house using more things will do it every time. Plus you are probably doing more wash than usual as you clean between guests.

If you don’t have them yet, buy water saving fixtures :), they will reduce energy usage by reducing the consumption of hot water :).

When I am not a host I work for an architecture firm, and we never specify heat-pump water tanks. They are very expensive and it is likely that you will need to replace the tank BEFORE the energy savings recoup the price difference (we have calculated that it takes at least 20 years). If you have gas in your house, you would better get a gas boiler, or get solar panels, especially in a warmer climate.

Do you mean tankless water heaters? They are all the rage here, that is, when there aren’t solar options, which are also really expensive.

The gas boilers I am referring to are tankless, they are pretty much a standard solution here and not really expensive, but they heat both the water and the house, which I guess you don’t need in Hawaï :smiley:. To comply with the energy standards in new construction, we usually need to install both a gas boiler and solar panels though, which gets expensive.

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It never ceases to amaze me how people always want to go into their room, flip on the light, walk out and leave the light running for hours while not in the room. How hard is it to flip off the light??? I just increase the rent rather than trying to stress over it. With my room rentals (long term) I tell them the utilities run anywhere from 35 to 75 per month depending on usage. I will be watching to see how much waste you create. I don’t care one bit when people are using the utilities, it is when they waste it that really ticks me off.

  • Change lightbulbs to LED (Do not change fluorescent tube without proper calculation, tubes are pretty efficient, and exchanging them is a big investment).
  • Put a timer/sensor on every light that is not needed permanently: Hallways, Toilets, Closets.
  • Put a timer on all fans.

And I always go into guestrooms after guests leave to check the lighst and heating. Some cultures have a lesser awareness about energy.

Interesting. Do you have a link or calculations you can send me? Though wouldn’t those calculations depend on the details, like how much the heater costs, how much labor costs, how much misc plumbing material costs, how much the cost of electricity is, and how much usage the water heater gets? If it was always the case that one could never recoup the investment, then it’s likely nobody would use them. Markets aren’t completely rational, but they are somewhat rational.

And when you say expensive, how much money are you talking about? And aren’t solar panels very expensive too? As I said already, the cheapest price I found was around USD 677. Though plumbing costs of rerouting the hot water through a single heater would be extra.

I was looking at, particularly the beginning discussion.and also

Though I have no idea how much electricity the existing water heaters are using, so I don’t know how to do calculations about it.

Oh, and we don’t have piped gas here, unfortunately, otherwise we’d go with a gas water heater probably. We get gas in tanks. I don’t think that would play nice with gas water heaters.

Hi @Chris,

Thanks for the comments. Could you elaborate on some of that?

We’ve already replaced many of the existing CFL bulbs with LED. But I think we still have some of them. Actually, we have a lot of fluorescent tubes; they’re our main source of lighting. Those are those long white tubes, right? Still, I thought that LEDs had them beat. And how would one do such calculations?

The timer thing certainly seems like a good idea.

I don’t follow the timer on fans thing. How would one put a timer on fans? Incidentally, we have people here who put clothes under fans to dry - mostly because they get sweaty. I don’t think this is exactly energy efficient, but I’m not listened to.

When you go into guestrooms, is that while the guests are still in occupation of the room but just temporarily absent? Or when they have actually departed?

WOw, doubled? My bill is the same, my guests have almost no impact on bill increase. I wonder why it doubled? DO they cook all the time or do laundry all the time, or take shower 12 times a day?

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No, LED has not really beaten the tubes.
If you got a good lamp holder with efficient mirrors, tubes give a lot of light.
You would need LED replacement with a lot of small LED’s to replace them, making the LED tubes expensive, and using a lot of energy.

Off course if you have a cheap lampholder a lot of ligt from a fluorescent tube is wasted.

With a good LED replacement you can save up to 50% of energy, but 50% of 42Watt’s is only 21Watt’s.
A good LED replacement tube costs about €45, and with an energy cost of about €0,25 per KWh.
The tube would need to be used for over 8500 hours to return the investment. That is a year, 24/7… that is a lot.
If they only run 4 hours a day, it is 6 years.
From a business point of view it is not worth the investment.

And 42watt (36W) tubes are big ones, most people have only 18W at home, wich make an investment even less attractive.

You have ceiling fans? I was talking about bathroom, toilet, but with a ceilinf van it is also possible.

Replace the wall switch with one of these (there are also 30 minute versions):

Yes, if they go out on a day trip.
I go in the room, check towels, toiletpapier, lights, heating, water the plants etc etc.
Just like in a hotel, hostel, B&B.
There is no reason why you are not allowed to go into their room.

Well I recently added a hot tub for my AirBnB guests. That should triple my electric bill, probably more in winter. It’s increased bookings dramatically and I was able to raise my average nightly price. So it’s well worth it :slight_smile:

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No cooking or laundry. And I don’t think they were taking 12 showers a day. Probably the normal number of showers for this part of the world - one or two a day. But they did seem to leave on the lights a lot. I’ve got a non-standard setup with the bathroom at the end of the balcony garden, and they’d go to the bathroom and leave the garden lights on. This would happen all the time - I’d always be switching them off. I’m thinking of putting them on a timer and making them two-way, so they can be switched on/off from inside the house and the bathroom. But, yes, double does seem like a lot. But is there any way to figure out the electricity consumption from a particular part of the house? Can one attach a meter to an electric line/cable?

Hi Chris,

Thanks for the insight into LEDs etc. We do have a lot of those tubes, and I’m don’t have any current plans to replace them. It would be a big job. And you are saying it doesn’t make much financial sense either. Do you agree that replacing CFL bulbs with LED bulbs makes sense? We are certainly doing that.

I’m not sure what the cost is per KWh in India. Does anyone? And is “per KWh” a standard measure?

Yes, we mostly have ceiling fans. But we just put a fan in the bathroom too. One of the guests complained. When I investigated, it turned out that there used to be a fan there, but it had gone bad and nobody had bothered to replace it. We don’t use the bathroom that is now the guest bathroom very much. I guess I could put a timer on it.

Question about timers: do versions exist that can be temporarily disabled? Preferably using a non-obvious method.

There seem to be different opinions on that. I don’t go in there when they are away (there’s a lock on the door). (a) to give them their privacy (b) to make it more difficult for them to accuse us of stealing.

Have no idea. Can ask my father, he used to work as electrician. If its only bulbs how can it double the bill though

Yes led lamps are 2x as efficient as CFL lamps and they use half the energy for the same amount of light. And they last far longer and they can be dimmed and they don’t need to warm up like CFL lamps. Go to the webpage, there are many other reasons led are better. And they are pretty cheap on Amazon. Interior designer here. And former lighting instructor.

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Thanks @Maggieroni, glad for the confirmation that I’m doing the right thing. But what on earth is a “lighting instructor”? :slight_smile:

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Well, the guest room has its separate A/C, which the guests are certainly running. Though we have two other A/Cs in the house, one of which (mine) basically runs non-stop because I have a computer in my room. The other A/C is also used a lot. Also a computer than runs 24/7, a TV, several electric water pumps, and lots of lights. Also the guest room is fairly small (150 sq ft) aggressively closed up, and the A/C is fairly new and has a 5 star rating.

So I would not a priori have expected such a big increase.

I taught lighting design at design college in SoCal