www.energystarhomesamerica.com

Issue 7 Volume 3

July 2005

Senate Bill #610:
A Tax Credit for Builders of Energy- Efficient Homes
by Jennifer Boyle
Fuel and energy prices have reached an all-time high and the trend is not reversing any time soon.  Fortunately however, Oklahoma legislators are addressing the energy issue as it pertains to homebuilding. Last month the Oklahoma State Senate and House of Representatives passed a bill that creates monetary incentives for builders and contractors who build energy-efficient homes.   Under Senate Bill #610, contractors will be rewarded with a tax credit proportional to the energy-efficiency of their newly constructed home.  For example, any eligible residence constructed and certified as between 20%-39% above the International Energy Conservation Code (IECC) shall receive a tax credit equal to the eligible expenditures, not to exceed $2,000 to the contractor.  For an eligible residence constructed and certified as 40% or more above IECC, the credit increases to no more than $4,000 to the contractor.  The strength of the proposal will rest with verification – it is required that a HERS (Home Energy Rating System) rater provide third-party verification to ensure the building performs as intended.  This measure will guarantee all of the technologies have been properly implemented with the energy savings reflected to the homeowner immediately.  Guaranteed Watt Saver, headquartered in Oklahoma City, is a local provider of such verification services.  Guaranteed Watt Saver has a staff of engineers and raters with over twenty years of experience in energy efficient housing. Included in the verification process is a blower door test to measure the air leakage of the building envelope, a Duct Blaster™ test to determine the leakage of the duct system, a window inspection, an insulation inspection and a complete analysis and review of all major building components to determine the efficiency of the heating, hot water and air equipment. For anyone living outside the Oklahoma/Texas area, a list of local raters can be found at www.natresnet.org and all of these services are eligible for credit under Senate Bill #610.

The bill is realistic, easy to implement and reaches out to mid-level income families as the credit only applies to new houses under 2,000 square feet. This is good news for everyone who’s been unable to reap the benefits of a new, energy-efficient home due to prohibitive initial cost. This bill also creates an incentive for homebuilders to implement energy-saving strategies in smaller, widely available housing.  

Expenditures eligible for the credit may include:

• energy-efficient heating or cooling system
• insulation material specifically designed to reduce heat gain or loss
• high-performance windows and doors
• metal roofing with the appropriate pigmented coatings

Senate Bill #610 is an excellent step toward rewarding responsible construction practices and will help ensure that builders do everything within their power to provide comfortable, affordable and sensible homes for their clients. As professional engineer Kelly Parker said, “It just makes sense on every level to build efficiently, the technology is right here - it’s just a matter of making it available to everyone.”

For more information, contact:
Guaranteed Watt Saver Systems
www.gwssi.com
405-946-0206
Inspector’s Corner
Heating & Cooling Load Analysis...
by Kenneth Lackey, DFW City Supervisor

This is a basic primer on determining the capacity of the heating and cooling system needed for your home or building. The acronym “HVAC” stands for heating, ventilation and air conditioning.

To save money on first cost as well as operating and maintenance of the HVAC equipment, it is important to size the systems according to the heat loss of a building in the winter and heat gain in the summer.  For most houses, a standard method is recommended for estimating the loss/gain (referred to as heating and cooling loads). This method is called Manual J, and is published by the Air Conditioning Contractors of America (ACCA).

Heat loss and gain is measured in BTU’s (British Thermal Units) per hour.

A ton of cooling (for air conditioning) is, by definition, 12,000 BTU’s per hour. If your house has a 32,000 BTU heat loss and a 35,000 heat gain, you need a 3 ton unit. With geothermal systems, it is particularly important to have an accurate load and to size the system to the larger of the two loads. The system should not be undersized based on the cooling load.

Manual J models how the house will perform on a relatively hot or cold day, using outdoor conditions that are almost “worst case”. These design temperatures will be used to determine the temperature difference (Delta T) and calculate the heat transferred across each of the components- wall, floor, windows, etc. In Atlanta, the design temperatures are 22 F for heating and 92 for cooling. The winter inside temperature is assumed to be 70 F and the summer inside temperature is 75 F at 50% RH. The moisture content of the outside air relative to inside air is also factored in by Manual J. This helps to determine the required amount of dehumidification needed by the air conditioning system.

This analysis can be done “whole house” on a floor by floor basis or by room-by-room. Unless the house is particularly large or has unusual architectural features, the whole house method is usually adequate for estimating sizing purposes. If the house will have multiple heating/cooling zones (areas that have independent temperature control) then room-by-room analysis may be needed. A copy of the plans or a drawing of the layout will be needed for a room-by-room analysis.

The major factors affecting heat gain in the summer are: window type and shading, orientation and size of glass windows and doors, heat gain through dark colored roofs, infiltration of moist air, and heat gain through insulation in ceilings and walls.

The major factors affecting heat loss in the winter are: heat loss through air infiltration (poor weather stripping, caulking, leaky windows and doors) and heat loss through the roof, wall, floor, windows and glass doors.

Heat losses and gains through ductwork are crudely based on the location (such as attic) and R-value of the duct insulation (duct leakage, which has been shown to be a significant problem in many homes, is not accounted for by Manual J). Appliances and base loads are assumed while ventilation fans that run continuously can also be modeled.

Basic information needed to run a load:

         Square footage by floor (or by room)

• Outside wall perimeter measurement by floor (or by room)
• Wall height by floor (to calculate wall surface area)
• Type of foundation
• Is basement occupied and conditioned or unconditioned?
• R-value of foundation or basement wall perimeter insulation
• If no basement, insulation value of floor above crawl space
• If slab, are ducts located in slab?
• Wall construction type, exterior finish and sheathing type (ex. 2x4 framing with interior drywall, ½ inch plywood sheathing and brick veneer or siding)
• Wall insulation R-value (if multiple wall types, include dimensions for each)
• Type of ceiling next to roof (ex. Ceiling under insulated attic, vaulted ceiling, shed or flat roof with batting type insulation, etc.)
• R-value of ceiling/roof insulation
• Attic knee wall area and R-value
• Roof color-either light or dark
  Now for the tedious part:

The type of all exterior windows and doors (wood frame double-pane, Argon filled, reflective glass, aluminum frame, single-pane, thermopane with storm window, thermally improved metal frame, solid core doors with or without storm doors, type of storm door, slider, French etc.)

• The size of each type window and door, either length and width or square footage
• Which windows and doors are located on which walls, by compass N, S, E, W, or NE, SE, SW, NW (this is needed to determine heat gain)
• What type of shading is available for windows, especially E-W-S orientations
• Number, type and orientation of any skylights, also pitch angle of skylights based on the roof pitch
• Number of fireplaces per floor
• Number of occupants per floor

We also need to estimate air infiltration of the building envelope for a home that has not been built. The simplified method is based on number fireplaces and construction quality (poor, average, best) although it is really more of an air sealing quality assessment. Guaranteed Watt Saver can either estimate infiltration or perform an air leakage measurement on an existing house or newly constructed home using a blower door and convert the results into infiltration values used by Manual J.

Announcements:
Attention Builders in the Dallas and Houston areas:
Please join us at the Greater Houston Builders Association for a comprehensive overview of the 2006 ENERGY STAR Guidelines on August 15th and again at the Dallas HBA on August 22nd.  Addresses and times are listed below.

Houston: 8/15                                                       
9511 W. Sam Houston Pkwy
Houston, TX 77064
Education Room (1st floor)
10:00 am (coffee & soft drinks provided)
For more info, contact Samantha Pearson
281-808-4512
spearson@gwssi.com

Dallas: 8/22
5816 W. Plano Pkwy
Plano, TX 75093
Conference Room
10:00 am (coffee provided)
For more info, call 972-931-4840
info@dallasbuilders.com
    

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