Residential architects who specialize in the hot, humid, southern climate

Greening your Bathroom

The terms “Green” and ‘Sustainable” are the hot new buzz words but when you consider that buildings are responsible for almost half (48%) of all greenhouse gas emissions annually it is imperative that we make our houses more environmentally responsible. Bathroom renovations create ample opportunities for saving water and energy. Begin your planning process by inventorying the existing space and determine your requirements. The survey should be broken into four categories; space allocation; water usage, ventilation and electrical usage, and materials and finishes.

Space Allocation: Best practices suggest that you design the space for your needs and not add additional square footage for resale value. If you only shower and never take a bath, do not add the extra square footage for a large soaking tub. A dedicated toilet closet will allow multiple people to use the bathroom at the same time and may reduce the number of bathrooms needed. Provide generous storage space; rooms can be smaller when there is ample storage space. Consider allowing enough space for aging in place; are the doors wide enough for a wheel chair or walker? Provide blocking in the shower walls for future grab bars.

Water Usage: There are huge water saving opportunities for bathrooms. An inexpensive solution is to replace existing shower heads with low water use showerhead. Old showerheads use up to five gallons per minute (gpm). Current federal law requires a maximum flow rate for of 2.5 gpm. One ultra low flow brands are Oxygenics showerhead 1.75 gpm for $30.00.

Toilets manufactured prior to 1992, use between 3.5 gallons per flush (gpf) and 7 gpf. Federal Law now mandates no more that 1.6 gpf for all new toilets. Many manufacturers are making super low flush toilets and dual flush toilets. The dual flush toilet typically uses 1.1 gpf for liquid waste and 1.6 gpf for solid waste. Available products include: American Standard FloWise™ 1.28 gpf for $359; Kohler Wellworth Pressure Lite dual flush 1.1/1.6 gpf for $451; Mansfield Eco-Quantum dual flush 1.1/1.6 gpf for $493; and Toto Aquia™ dual flush 0.8/1.6 gpf for $435. Another option to consider is a composting toilet that uses no water; they cost about $2,000.

Heating water typically uses between 14 and 25% of a household’s energy. Three options in water heating are Solar, conventional storage tanks, and tankless (on-demand) heaters. Solar Water Heaters are the most efficient but also have the highest initial costs ($4,500 to $9,000). Solar Water heaters are either a passive or active system. The passive systems are less expensive, more reliable, and have a longer life. The passive systems are not as efficient as active systems.

When selecting a conventional water heater look at the EnergyGuide label and the Energy Factor which rates the overall efficiency of the unit, the higher the number the better. The standby heat loss of traditional water heaters can be lessened with heavily insulated tanks. The thermal resistance (R-Value) of the tank should be between at minimum R-12 and preferably R-25.

Tankless (on demand) water heaters are gaining popularity in the United States because they save between 15 and 40% of water heating energy costs. The cost of the unit typically is about twice the cost of a conventional tank water heater. They are available in both gas and electric models. Popular brands include Rinnai and Bosch.

Mechanical Systems – Ventilation and Electrical – In bathroom remodels, the changes to the HVAC is limited unless you are replacing the entire system. At the very least you need exhaust fans vented to the exterior. Best practices include installing the fans on a timer to shut off thirty minutes after use.

The bathroom lighting needs to include general overall lighting, task lighting at the lavatories and a ceiling light in the shower. Consider separate switches for the three types of lights to minimize energy requirements. Look for EnergyStar qualified light fixtures, they typically use 75% less energy, produce 75% less heat and last up to 10 times longer than a standard fixture.

Materials and Finishes – The materials mantra is reused first, recycled second, and purchase rapidly renewable resources third. In a renovation project, deconstruct instead of demolish the existing space. Reuse all the existing material that you can. Donate or recycle any material that is not used to keep it out of the waste stream. Look for salvaged building materials to use in the project instead of purchasing new products. Recycled products reduce the burden on our landfills and conserve our resources. Locally manufactured products are preferable because of the reduced energy requirements for transportation.

Bathroom finishes should be durable and water resistant. Ceramic tile with recycled content is the best option for walls and floors. Stone is a very durable option but because it is not local to the Lowcountry the shipping costs make it a less environmentally friendly selection. Natural Linoleum is made from linseed, oil, jute, and wood dust and is the preferred alternative to vinyl flooring. Care should be taken in selecting adhesives that contain low VOC’s (Volatile Organic Compounds).

In our hot humid climate, wall paper, especially vinyl wall paper, should not be used. The wall paper acts a vapor barrier; moisture is trapped behind the paper and provides an ideal condition for mold. Carpet is another bad material for bathrooms because it also traps moisture.

Indoor air quality is affected by off-gasses from cabinets and paints. Cabinets should be constructed from materials that contain no added urea-formaldehyde resins and paints should be low VOC. Solid wood is a healthy alternative and should preferably be certified by the Forest Stewardship Council (FSC).

Resources – Some helpful websites are