Tackling ventilation and air conditioning can involve a few different measures. The most common upgrade for ventilation systems is variable speed drives. These drives fine-tune the fresh air supply based on either a schedule or air quality monitoring. There’s also the option to use heat recovery ventilation, transferring heat from stale exhaust to incoming fresh air to substantially reduce energy use. High-efficiency chillers can dramatically reduce electricity use for cooling. Many buildings can actually benefit from free cooling systems that use cool outdoor air at night, or during spring and fall, to supplement traditional cooling systems.
Renewable energy projects, such as solar power, come with a high up-front investment, but offer a big payoff. For solar photovoltaic installations, your building must have a large roof area or a south-facing wall to reap the most benefits. These solar photovoltaic measures can offer compelling long-term returns under the Feed-in Tariff program. You can also go the solar thermal route, which also requires a large roof area or south-facing wall, and can be used to pre-heat domestic hot water or ventilation air. Ground-source heat exchange can provide dramatic efficiency improvements in certain suitable buildings.
Since space and water heating account for the lion’s share of energy use and greenhouse gas emissions in most buildings (50–70%), finding energy efficiencies here is often the best bet for savings and reductions. A boiler tune-up can often boost the efficiency of older boilers (which waste over 30% of the energy they produce) by 10%, while new, high-efficiency boilers are available from 85–95% efficiency. Low-flow showerheads and faucets can also substantially reduce hot water demands, thereby increasing the efficiency of the system.
The walls, windows, doors, and a building’s roof — the building’s envelope — have a major impact on energy performance, specifically heating and cooling demands. Air leakage (gaps around windows, for example) and thermal losses (from poor insulation) account for a large amount of energy loss. Improving envelope performance can be as simple as caulking and weather stripping around windows and doors. In older buildings, there are a multitude of major upgrades that improve energy performance, reduce maintenance, and refresh the building’s appearance. For example, exterior insulation finishing systems provide insulation and can extend the building’s life. Replacing older windows with new high-efficiency windows can also reduce energy-use, while improving comfort levels inside the building.
Building automation systems and smart controls can shave as much as 10% off a building’s energy consumption. Energy monitoring systems keep real-time tabs on your energy use, so you can identify and solve problems faster. The best opportunities for improvement are often building-specific. These can focus on syncing up major mechanical and electrical systems, or fine-tuning heating, cooling, and lighting for particular zones. In many cases, simply having the ability to track daily energy-use patterns can lead to major savings by exposing hidden malfunctions and problems.
Lighting accounts for 5–10% of total energy use in most buildings, mostly in common areas where lights can be left on up to 24 hours a day. Almost all buildings can improve their lighting efficiency. Plus, lighting upgrades are low cost and usually pay for themselves within three years. Switching to energy-efficient light sources like LED and high-efficiency fluorescents, as well as advanced lighting controls like sensors, can have dramatic results.