October, 2007
Inspection News and Views from the American Society of Home Inspectors

In-Deck Solar Pool Heating


Radiant Panel Association members are continuously finding innovative ways to use radiant technology. Dexter Carpenter of Dexter’s Solar Radiant Energy Services in Santa Barbara, Calif., utilizes the radiant-floor concept in reverse to heat swimming pools. Dexter gives us some pointers, as follows.

“One of the most important factors of an in-deck pool heating system,” says Dexter, “is the ratio of the deck area to the swimming pool surface area.” In Santa Barbara, Calif., the ratio of deck area to pool area needs to be 2 to 1. For example, if the surface area of the pool is 800 square feet, the sunlight-exposed deck area has to be at least 1,600 square feet.

What is also important is to have the un-shaded deck area in full sun for at least six hours a day so the concrete can absorb heat to be later transferred into the pool.  Umbrellas and lounge chairs will reduce the solar exposure to the deck.

Dexter runs pool water directly through the tubing embedded in the pool deck using a typical pool pump. The in-deck solar radiant heating system should have its own independent supply and return lines to the pool. “And why not?” Dexter points out. “As the pool is being built, the opportunity exists. Just ask. The pool builder will install the dedicated plumbing.”

Another important aspect of the in-deck design that Dexter points out is the placement of the tubing in relation to its depth in the concrete deck. Ideally, the tubing should be in the top one-third of the deck. To achieve this position, extra rebar or 6x6 wire mesh needs to be installed so the tubing can be tied down with the proper 6-inch-on-center spacing and held at the proper height in the deck.

Having color in the concrete will increase the deck temperature and, in turn, the pool water will receive more heat. Adding a stone or a brick finish to the pool deck will decrease the system performance to a point of non-performance. “Don’t bother doing the job,“ Dexter says.

The system is controlled as follows. A recoverable sensor is installed in the deck at the same level as the tubing. A differential control monitors the pool water and compares its temperature to the deck temperature. When the deck is warmer and there is a need for heat, the control activates the solar pump. The pump circulates the pool water through the tubing in the deck, where it extracts the solar heat and returns to the pool.

Dexter says, “All snow-melt systems are solar collectors itching to be drawn from.” He has done a few tennis courts as well. They work great because there is no shading, unlike driveways where cars are likely to be parked.

Dexter’s customers are happy because, as he points out, “When the system is operating properly, the deck becomes cooler, more comfortable to walk and lie on, and the pool heats up.”  It is a simple solution that can save a lot of energy while making life by the pool more pleasant.

Reprinted with the permission of the Radiant Panel Association, 800-660-7187, www.RadiantPanelAssociation.org.

Green Remodeling

Consumers want their remodeling projects green and remodelers already answer the call, according to recent research by the National Association of Home Builders (NAHB) Remodelers.

Further evidence of the trend: For the first time, the National Green Building Conference held remodeling educational courses for contractors.

More than one-quarter of remodelers surveyed by NAHB saw growing demand for green remodeling late last year, compared to just 6 percent reporting less demand. The majority of remodelers already incorporate energy efficiency into their work. Nearly all (85 percent) used low-energy windows, 68 percent used insulated exterior doors, 65 percent upgraded insulation, and 56 percent installed high-efficiency HVAC systems.The survey also showed that many remodelers also use environmentally friendly products. For example, more than 75 percent of those surveyed minimize the harvesting of old-growth forests by using alternatives to dimensional lumber, like engineered wood. Additionally, 65 percent already incorporate recycled or recyclable materials into their projects.

NAHB Remodelers offer a “Top 8” list for homeowners:

  • Install maximum insulation in the area to be remodeled.
  • Install high-efficiency windows instead of those that just meet the energy code.
  • Seal all exterior penetrations in the area being remodeled.
  • Purchase only Energy Star®-rated appliances.
  • Install only low-flow water fixtures.
  • Upgrade to an Energy Star®-rated water heater, or better yet a tankless water heater.
  • Purchase the highest efficiency HVAC system you can afford.

Source: www.nahb.org/remodel