Meet your energy needs with efficient systems that work together. Make your building a finely tuned, lean, green machine.

When you adopt green building, energy savings are the greatest payback for the costs of high performance, efficient design and systems. Energy efficiency is an integral part of building green, and requires integrated design and careful calculations from day one. Proven energy modeling software lets you design the building systems for greatest efficiency at the lowest cost.

Reduce your building's energy requirements.

As you aim to design comfortable, efficient homes, your first move is to figure out how to heat, cool, and light your building with the sun and wind. Start by orienting the building to take advantage of sun angles and prevailing winds. Surrounding buildings and trees can provide shade in summer and to block winds in winter.

  • Passive solar heating uses properly sized and oriented windows to heat thermal mass that stores heat and keep temperatures where you want them.
  • Passive cooling allows for natural ventilation for spring and fall (where outdoor air is clean and noise levels low). Windows with low-emissivity ("low-e") coatings guard against the high summer sun.
  • Daylighting can replace electric lights for hours at time when you design floor plans and window details to let in the sun.

A high performance building envelope can block, hold, and release energy to let nature work with your design. Much of your investment here will also pay off in reduced construction costs, not to mention lifelong savings.

  • Step one is effective insulation, foundation to roof. When you invest in windows with high R-values and a tight building envelope overall, you can usually recoup the cost with smaller cooling and heating systems.
  • Take care to avoid thermal bridging at structural joints and install reflective (or light colored) roofing to keep cool in summer.
  • The need to maintain a tight skin for your building extends to eliminating all leaks. Seal between floors, stairwells and elevator shafts, hallways, and around all ductwork and even electrical system housing. Weatherize exterior and unit 'front' doors and use double doors at building entrances. Then take care to provide adequate ventilation and to balance HVAC systems.

Meet your energy needs with efficient systems that work together.

Make your building a finely tuned, lean, green machine.

  • Design and size heating, cooling, ventilation, and plumbing systems that efficiently meet the needs of the building. Integrated design allows this to happen as you consider the site, orientation, envelope, lighting and other variables.
  • Optimize each system's performance alone and in concert with the other building systems. In a housing development, your goal is comfort and efficiency for each unit, not just the overall building.
  • Calibrate and monitor. Consider a computerized energy management system that can track loads and system response, then make adjustments to maintain efficiency. HVAC balancing will work best if you go one room at a time.

As you specify systems, lighting, and appliances, make efficiency a priority. The result will be better components and a better building.

  • A high quality electrical system cuts fan and motor energy consumption and reduces waste heat from components. You can save more by installing energy efficient lighting and appliances. EnergyStar is an excellent guide.
  • Adaptable systems such as modular boilers, variable air volume ventilation systems, and independent mechanical rooms let you respond to changes in demand and improve performance.
  • High performance air conditioning and gas heat are your best baseline choice. For even greater efficiency, consider radiant heating or combined space and water heaters. Heat recovery systems, both variable and latent, put waste heat to use. Desiccant dehumidification systems can decrease cooling loads, especially in humid Washington, D.C. area summers. You will realize significant energy savings by keeping ductwork in conditioned spaces.
  • Water-saving showerheads and faucets, in coordination with efficient hot water heating and delivery, also offer considerable energy savings.

Encourage energy efficient living

Residents will best benefit from your energy efficient building if they have control and responsibility. Meter each unit, or at least make sure that residents know their electricity and gas use. Then give residents smart controls to adjust the heat and AC and make it easy to switch off lights and electrical outlets. Show owners and tenants how to get the most out of the sun and wind with education on natural ventilation and window shades.

Clean energy and renewables

Passive solar heating and daylighting are the best use of renewable energy, but much more is possible once your building is energy efficient. The payoff might be 10 to 15 years away, but subsidies may be available to offset the initial cost of these technologies.

  • When you pair a solar hot water system with an efficient central boiler, you can cut water heating energy use by up to 70 percent. A geothermal heat pump can reduce heating and cooling costs even more.
  • Generating electricity onsite with photovoltaic panels can run the meter backwards for a single family home. Wall and roof panels with integrated solar cells make it easier.
  • Opt for cleaner sources of energy, such as utility company steam, natural gas boilers, and cleaner-burning grades of fuel oil. Gas-fired microturbines and fuel cells can be cost-effective sources of electricity and heat for larger developments.
  • Consider purchasing renewable from the electric utility for the entire development. Contract purchases can give you a guaranteed lower rate for a specified number of years.

Infrared photo of a poorly insulated house leaking heat energy.


Best Practices:

Top Five Do-it-Now for Energy Efficiency, from PATH

Energy Efficient Rehab Advisor, HUD

Energy Efficiency in Existing Homes, A PATH Roadmap

Standards and Programs

ENERGY STAR and ENERGY STAR for Affordable Housing, US EPA

Green Communities Criteria-Energy Efficiency and Energy Star, An Enterprise Live Online Event

Building Better Affordable Housing in New York City: Getting ENERGY STAR or Equivalent Ratings, Steven Winter Associates, Inc.

Systems Efficiency:

HVAC: Forced Air System, PATH Tech Set 3 best practices

Energy-Efficient Lighting, PATH Tech Set 3 best practices

The Sun in the 21st Century Home, PATH Tech Set 3 best practices

Efficient Windows Collaborative and All about energy efficient windows, Fine Homebuilding

Key Resources:

Pacific Energy Center This utility-funded center in California is a leading resource for energy efficient design.

Database of State Incentives for Renewables and Efficiency, North Carolina Solar Center and the Interstate Renewable Energy Council

Daylighting at the green HIPP artist apartments in Mt. Rainier, MD