Tuesday, December 04, 2007

If Not Carbon Offsets, How About Automation?

Ok, no bites on my tease about Carbon Offsets. Raters at Helium had a similar reaction, consistently rating it last of the articles submitted on the subject. I get the message...forget the teasing satire and stick to what we can really do to address our energy issues. If you are really interested in carbon offsets, check my more reasoned and balanced rewrite on the subject on Helium (check ads on my blogs to get there).

If not carbon offsets, have you considered automation? I've briefly mentioned this before as a potentially significant part of the solution to energy issues, but have not explored it in detail. When the term automation is mentioned, most people think of complex control of giant factories, and certainly there is much room for this approach. But simpler approaches around the house have substantial potential as well, so let's look at some ideas in this area.

One often overlooked area is your electric water heater. When used as resistance heating, as with your water heater, electricity is one of the most expensive and inefficient energy sources out there. Worse, your water heater keeps using electricity to heat water, even when you are not using any hot water. This is because it heats a large tankful of water, which is constantly leaking heat through its insulation even if no water is used. Often this wasted heat is as much as 50% of the energy used for water heating. Consequently, depending on where you live and your lifestyle, water heating is probably your second or third largest user of electricity. Fortunately it is reasonably easy to cut down on this waste without much inconvenience. Simply install a timer. Then set the timer to turn the power off to the heater when no one is using hot water, such as overnight, or while everyone is at work. Actually, due to the large storage of hot water, reasonable amounts of hot water will still be available even when the water heater is turned off. Unless you have a high demand for water, such as mutltiple loads of laundry or several people showering, you can probably get by with running your water heater just an hour or so a day, say just before the alarm goes off in the morning. Most timers have a manual on/off switch as well, making it easy to turn the water heater off when you are away from home for the weekend or a vacation, or on if you anticipate large loads on a specific day. Due to the high voltages involved, you'll probably need to have an electrician install the timer unless you are fairly knowledgeable about electrical work, but even so it will likely pay for itself in a few months.

And consider your heating and cooling system, likely the largest energy user in your house. A setback thermostat allows you to turn off (or down) your heating and cooling when you are not there to enjoy it. And it is relatively easy and safe for a handyman to install. Just buy it at your local hardware store and follow the instructions. Again, depending on your lifestyle, payback is just a few months. If you want to go further, it is possible to install motion detectors that heat or cool an area only when it is occupied. The equipment and controls required are a bit more complicated than for the setback thermostat, but now you are potentially talking about much bigger savings.

What about your lighting? Do you leave your outside lighting (including Christmas lights)on 24 hours a day? Consider adding a timer, photocell or motion sensor, depending on when you want the lighting on. It is likely you can save a large percentage of the energy used on outside lighting and still accomplish your objectives. It is even possible to add motion sensors to inside lighting to cut off lights that are not being used, though the timing and equipment is a bit trickier.

And, consider your electronics. Your TV, your stereo, your DVD player, your WiFi setup. Again, they all use electricity even when turned off. A simple, plug-in appliance timer will stop the electricity flow at say, bedtime, and return it when you are likely to want them on, say breakfast or quitting time the next afternoon. You can always manually switch them on if you find you need them. Again, the few dollars in investment will be returned within a few months.

If you have peak rates, where electricity is more expensive at certain times or is based on a maximum demand, you have even more potential to save with automation. Just set any equipment that can run any time to run at the times when power is cheaper. The water heater and heating and cooling system fall into this category. Just use your timer. Even such items as your freezer need run only a few hours a day. Use a timer to make them do their running in off peak times.

If you use your imagination on your own home, you'll likely find even more applications. But what is clear is that you can reduce your energy costs substantially with simple automation. Your returns on investment in the equipment needed will likely exceed any other investment you can make. And instead of spending money on questionable carbon offsets, you'll save money with the certainty of reducing your environmental footprint. Take that, carbon offsets!


Hitotsu Ningen said...

Man, these are great ideas. What do you know about tankless water heaters? I've seen several on eBay for $300 to $400 delivered that appear to meet my home's current and future usage requirements. I just don’t know much about them. I would have to go with an electrical tankless water heater given I don’t have natural gas at my home. I think I could figure the ROI but I don’t know much about the pros and cons for this sort of set up other than the labor that it would require in the installation.

max said...

I'm not an expert on tankless water heaters, but I have used a few of them in Trinidad and the Netherlands and understand the concept.

The advantages of tankless heaters are:

1. They do not store a lot of water, so they do not "leak" as much energy from the stored volume.
2. They can supply their rated amount of hot water continuously. This is in contrast to tank type water heaters, which have a certain volume of water stored, but when that is used up you will have no hot water until it heats some more.

The disadvantages:
1. They can not supply a larger amount than their capacity, in contrast to tank type water heaters, which can supply as much as you can get through the pipes until the water is gone.
2. They require a large energy supply, since they are heating all the water as it is being used. In contrast, tank type heaters might take an hour to reheat the water you use in 15 minutes, so the energy supply does not have to be as large.

The tankless heaters I have used were all gas, as are most tankless heaters. This is because it is easier to get the concentrated high heat input with gas than with electricity. Even so, there are electrical heaters. Just be prepared to run heavy wires with a big breaker, or to accept a relatively small capacity.

Essentially, with tankless, you trade higher temporary capacity and the associated leakage for continuous availability and a more expensive installation.

Before you consider installing tankless, you probably need to do some research to make sure you understand your hot water usage and can match it with tankless at a reasonable cost.

Tankless are also have a bit more complex control systems, with which I've had some problems, but presumably a modern heater would eliminate these issues.

I haven't done the research, but for my money I'd probably minimize the leakage with insulation or a timer and stay with the tank.

Solar John said...

I've recently enrolled in a peak-rate plan, and I expect to pay as little as 2 cents per kwh after midnight. I'm thinking about charging batteries at that time, and using the stored power during the day when rates are highest. I already use batteries to a certain extent with my small PV system. I write about my projects on my blog:


max said...

Solar John:

That rate ($.02/kwh) is a great rate. That should really help justify various energy storage mechanisms. I'm not sure a battery is the best way to do it, though. Batteries are pretty expensive for the amount of storage they give. They also have a relatively short life.

My preference would be to store the energy in the form of heat. Ie, run your HVAC, freezer, water heater, etc during the off peak hours. This effectively stores the energy in the form of heat. If you want to store more than can naturally be stored with these systems, you could add water or thermal mass to the spaces or add a specific, well insulated room. Then, heat or cool during off peak hours and withdraw it during peak hours.

This way you can get most of your hvac, hot water and refrigeration from off peak hours, storing it simply in insulated space. If you can do that, you can get most of your usage at the off peak rate.

I'm planning to do an article on this in the near future.