Swimming Pools: Save Energy While Enjoying the Summer Heat

Is there an Energy Hog in your pool?

 

If you have a swimming pool, you probably hate to see your utility bills during the summer. Chances are, you’ve attributed the high bills to your air conditioner. But pools and their associated pumping equipment might be responsible for at least as much energy use as that big central air conditioner!

Why does the pool use so much electricity and is there anything you can do about it?

Pumping water takes a lot of energy. Just think about the last time you took a swim. It takes all your energy to swim the length of the pool, while you could walk this distance without difficulty. In the same way, moving water, because of its weight and resistance to flow, requires a lot of energy.

So if moving water naturally takes energy, how can you reduce the consumption?

Without getting too technical, moving a gallon of water through pipes takes much less energy if it is moved slowly than quickly because of water turbulence. Just knowing this allows you to dramatically reduce your pool pump’s energy use.

Unfortunately, most pools are designed with vastly oversized pool pumps. For example, my pool had a 1.5 horsepower (HP) pump. This is useful for backwashing the filter, but for general filtering, using such a huge pump results in less efficient filtering and much more energy consumption. Worse, that 1.5 HP pump might pump less than twice as much water as a .5 HP pump due to the high turbulence caused by the larger pump.

You’ll find that running that 1.5 HP pump for 10 hours a day (fairly common for pool pumps) will add about 15 kilo-Watt-hours to your electric usage. For many households, that’s an increase of 30%-50% of the home’s total daily electric consumption! Over the course of a summer, that adds up to hundreds of dollars in increased electric bills.

For my pool, I installed a two speed pool pump that allows me to run at 3/8 HP for general filtering. The water flow is ample for filtering yet it uses about 1/8th the electricity as when it runs at 1.5 HP. The only time I turn it on ‘high’ is when I’m backwashing the filter. Other than that, it runs 12 hours per day at a few hundred Watts (a total of about 3.6 kWh/day). When I convert kWh/day savings (over 10 per day) to dollars, I’m saving more than $1.60/day which is about $150 per summer in saved electric bills.

If you’re building a new pool or replacing an old pump, installing a multi-speed or variable speed pump is a no brainer. At a cost of about $500 for a high end two-speed pump or $1000 for a variable speed, the savings will pay for the pump in a 3-6 years. About half that if you’re replacing an existing pump and would have to buy a new pump anyway. Pu another way, that’s like having an investment that pays 15%-30% dividends – in these economic times, you’re not going to find a better investment!

Your specific numbers will vary depending upon your electric rates. I pay a lot in eastern Pennsylvania, so any electric savings pays back quickly. If you’re in an area with cheap electricity, the payback won’t be as quick.

The Sustainable Building Advisor Institute

It’s been a busy week for me with my startup, OurKudos.com, so I haven’t had much time to contribute to Ted’s Tips. But now on a rainy Friday night, I feel the need to decompress and talk about energy efficiency and sustainable building again!

I got an announcement today from the Sustainable Building Advisor Program, an organization dear to my heart. They have changed their name to the Sustainable Building Advisor Institute and launched a new website.

Why is this so exciting? The SBA program is a wonderful organization dedicated to training people in the world of sustainable building. Unlike so many organizations that have sprung up in the last few years simply to make a buck on the “green” excitement, the SBAi is truly about the teaching. It’s a very small organization of dedicated individuals, passionate about what they do.  Continue reading

The Energy Geek Video: Sun Tubes and Skylights

My first Energy Geek video! This is the companion video for the recent article on Sun tubes.

Don’t expect much production quality. These videos will be like this blog – unedited, not politically correct, lots of opinions. So if you’re expecting “This Old House” you better look elsewhere!

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FAQ for Solatubes

Bright Ideas for Saving Energy #5: Sun Tubes

What’s better than a sunny day? A sunny day that helps illuminate the normally dark recesses of your home!

Normally, people install skylights – basically just windows built into the roof. But skylights have several problems:

  • They’re incredibly energy inefficient. Even a good, double glazed, low-e unit is a poor insulator.
  • If they’re not facing the right direction, they don’t let any direct sunlight in during the winter and too much during the summer.
  • They’re difficult to keep clean unless the roof slope is gentle.
  • They’re prone to leakage due to ice dams created because of heat loss around the windows

A sun tube works differently than a skylight. Instead of being large windows in the roof, they’re typically smaller, about one foot to sixteen inches in diameter. Right away, this is beneficial because energy loss is directly related to the area of the opening. So a 16″ sun tube has an area about one third to one fifth of a typical skylight.

Sun tubes are built with reflectors so that they bring light into the house even as the sun moves to a variety of different locations. Usually, they are set up to reflect the Winter sun optimally but they can work well year round. I’ve installed several in my own home and really like them. One is in my office, which is on the north side of the house and never gets direct sun through the windows. However, the slope of the roof is such that for most of the year, the reflectors on the sun tube can capture sunlight and direct it into the normally gloomy room. Here’s a cheesy video demonstrating how these products work.

During the summer, sun tubes brighten rooms without heating them up like conventional skylights. If you’ve ever stood under a skylight during the summer, you know what a problem this can be. You can get a tan under some skylights! That definitely doesn’t help your air conditioning bill. Solatubes bring in the light, but due to their relatively small size and the way they work, the amount of heat that they bring into this house is very low.

Installation of sun tubes is easy. I installed one  myself, and I’m no carpenter. I just followed the directions and it went in easily. Granted, I am pretty good with a saw and don’t mind crawling around the attic. However, if you’re not up to it, there are usually “factory certified” contractors who have been trained to do the installation.

There are a variety of manufacturers of sun tubes, but my favorite is Solatube. They have residential and commercial versions are well made and easy to install. Please note – I have no business relationship with them. I’m just a happy customer!

Another nice feature of sun tubes is that they can act like light fixtures when you need electrical lighting. A simple bulb holder can be installed into the tube. Yes, it blocks a little of the light, but I’ve found this to be well worth it in the rooms where I’ve installed them.

Are they perfect? No. If you don’t like white, round plastic portholes in your ceiling, you’re out of luck. Additionally, the tubes are fairly cheap and easily damaged if you’re not careful. However, you only handle them during installation, so that’s not a big deal. They also need to be installed in rooms directly below the attic or roof because it’s a sun tube! It only directs light a few feet from the roof into the room. So they’re ideal for ranch houses or upstairs rooms but of no use on the first floor of two or three floor homes.

Other than that, I love these things. There are some rooms in my house where I almost never have to turn on the lights. If I could have, I would have installed several in my kitchen and living room.

 

Question: What are your thoughts on solar heated water?

Question: What are your thoughts on solar heated water?
Answer:

Solar water heaters are one of the most underutilized alternative energy systems in the U.S. What could be better than reducing your energy consumption using the sun? Many other countries have “got it” and you’ll see solar water heating systems on most roofs.

There are three problems with them – we charge too much ($7000-$10,000), there aren’t enough qualified installers and they require maintenance. But if sized and installed properly, most families could satisfy 75%-90% of their hot water needs using solar on any sunny day.

Here are some resources for further reading:

Build it Solar – Site for solar DIY’ers.

U.S. Dept. of Energy

Wikipedia – Extensive article on solar water heating