Corporate

Heating and Cooling

Next to the integrity of your building, the efficiency and usage patterns of your heating, ventilating and air conditioning systems (HVAC) have the most marked effect on business energy costs.

The suggestions listed below can help you reduce your usage by as much as 30 percent. You can accomplish your goals by using the HVAC system less, changing temperature settings, and replacing equipment with more efficient designs.

You can make the simple and moderate adjustments yourself, but you'll need to consult a heating and air conditioning contractor to make decisions about more efficient equipment.

General Heating and Cooling Considerations

Sizing Your System
One of the common mistakes businesses make is using heating and air conditioning systems that are inappropriate to their space needs or particular activity.  Restaurants and dry cleaners, for instance, need larger capacity air conditioning systems to handle their high heat output.

If you run your heating or cooling system for long periods of time and still can't keep temperatures in the comfort range, you probably need to talk with an expert.

On the other hand, a heating system that is too large for your needs will also cost you money in reduced seasonal efficiency.

Types of Equipment
Although the climate of the mid-Atlantic region is relatively mild, most businesses need to operate equipment during both the heating and cooling seasons.  Depending on the age of your building, these may be separate units, or integrated, total environment systems.

  • Heating
    Most businesses use forced air, hot water, steam or electric heat sources. Electric systems usually offer a high degree of flexibility, with different controls for different areas of a building. Other types of heating sources (oil, gas, coal or sometimes wood) are generally classified as central systems, generating heat at one point and moving it through the building by pipes or air ducts.
  • Cooling
    Most businesses use either window units or a central air conditioning system that distributes cool air directly or through ducts or registers. Technically, air conditioners may be classified as air-cooled condensers, water-cooled condensers, cooling towers, evaporative condensers, self-contained equipment (window units), remote or split units, or built-up systems. Air-cooled condensers are by far the most common for both commercial and residential use. Heat pumps are popular with businesses because of their high efficiency and the fact that they provide heating and cooling in a single system.
  • Ventilating
    Windows that open are the simplest kind of ventilating equipment. At the other extreme are total environment systems with advanced features like variable air volume. The new systems use ducts, fans and dampers to draw in fresh air, mix it with inside air, and remove stale air from the building. Proper ventilation provides air for breathing; removes smoke, odors and vapors; reduces heat; and provides air movement around occupants.  The amount of air movement that is best for your establishment depends on the type of activity you're engaged in.  In addition to ventilation, air quality and humidity have a major impact on employee and customer comfort.

Combustion Efficiency
How thoroughly a heating system uses oil or gas when it is running steadily is known as combustion efficiency. [For electric heat pumps, operating efficiency is referred to as the Coefficient of Performance (COP)].  Up to 40 percent of the energy produced by oil or gas heating systems can be lost through the sides of the equipment or up the chimney or flue.

With oil or gas systems, combustion efficiency is affected by the amount of air in the fuel mixture, dirt on the furnace nozzle, boiler sediment, and soot buildup in the combustion chamber.

Efficiency is generally measured from Poor (65 percent or lower) to Excellent (85 percent or above). A service technician can tell you what the combustion efficiency or COP of your system is and improve it with a seasonal tune-up.

Seasonal Efficiency
If you think of combustion efficiency or COP as the measure of performance for an operating system, seasonal efficiency is an indicator of how well your heating or air conditioning system performs over an entire season of starts and stops.  Seasonal efficiency is a truer indicator. It takes into account the energy that's lost whenever your system shuts off and in some cases, energy used for fans, controls, etc.

In the vocabulary of the heating and air conditioning trade, the efficiency of an air conditioner or heat pump in the cooling mode is shown as its SEER (Seasonal Energy Efficiency Ratio); the heating performance of heat pumps is expressed as HSPF (Heating Season Performance Factor); and the heating efficiency of oil or gas furnaces is known as AFUE (Annual Fuel Use Efficiency).

Your contractor may be able to improve seasonal efficiency by downsizing your system, reducing flue losses or adjusting your controls.

If You Have Heat Pumps
Heat pumps are popular in homes and businesses in the mid-Atlantic region. Heat pump technology is the best way to both heat and cool your premises from a single efficient source. 
By virtue of its technology, the heat pump moves more energy than it uses during the heating season, extracting heat from outside air and moving it indoors to heat the space.

Newer heat pumps are far more energy efficient than their older counterparts, as evidenced by rising SEERs.  They also produce considerably warmer air in the heating mode than previous models, creating a higher level of comfort.

Your contractor may be able to improve seasonal efficiency by downsizing your system, reducing flue losses or adjusting your controls.

Setting Your Heat Pump Thermostat
Unlike combustion systems, heat pumps generally should not have their thermostat settings reduced at night or on weekends. (This only applies to the heating season. You should turn your air conditioner off during non-business hours if the nature of your business allows it.)

The explanation is simple: When you bump your thermostat up again at the beginning of the workday, your system will call on its back-up heat to get the temperature up quickly. Because back-up heat doesn't use the heat pump's more efficient technology, the extra cost incurred by using it each day is often more than you would spend by leaving your thermostat at the same setting throughout the heating season.

The optimal solution is an automatic, programmable thermostat designed for heat pumps; this limits back-up heat use by raising temperatures in small, incremental boosts. To explore this option, contact your heating and air-conditioning contractor.

Planting Around a Heat Pump
View a video featuring information on plants to use around heat pumps to save energy, plus fall planting and safety awareness tips.  It features Dominion Energy Conservation Specialist Alison Kaufmann and Tom Brinda, horticulturalist & Assistant Executive Director of Lewis Ginter Botanical Garden.

 

Simple and Inexpensive Projects

Lower Your Thermostat in Winter
No matter what type of heating system you have, a small reduction in the normal workplace temperature can make a significant difference in your fuel use. In fact, for every 1°F reduction you will save approximately 3 percent in total energy.

If you gradually reduce the temperature -- try one degree a week -- you can make the change relatively painless. Cut 5°F from both your day and night settings and you can reduce your winter heating needs by about 15 percent, a return many businesses find well worth the small sacrifice in comfort.

Your building may also have uneven heating patterns that force some employees to endure high temperatures so that workers in colder areas will be comfortable.

An energy expert may be able to adjust your system to alleviate uneven temperatures. If adjustments prove insufficient, you can investigate space heaters for these cold spots so you can reduce the overall temperature setting.

Higher Settings in Summer
There are even greater savings to be had from raising your thermostat in the summer - up to 5 percent per degree.  Nudge the setting upward over time until you reach a good balance between energy savings and comfort (usually around 78°F).

Your customers and suppliers will still feel a welcome contrast when they enter your building. And if your employees perform desk work or other low activity tasks, they will probably be just as comfortable in a slightly warmer environment.

Are Your Thermostats Accurate?
Let’s say you’ve set your winter temperature at 68°F and your summer reading at 78°F. The only way to make sure that these temperatures are accurate is to verify them with a reliable thermometer. (Buy one if need be).

Take your readings next to each thermostat, when the temperature is stable; then adjust the setting up or down if necessary.  In some buildings, you may have to work with the maintenance staff to adjust thermostats.

Locking Your Thermostats
Adding security enclosures to your thermostats should be considered as a last resort.  If you find that people reset them, visit with each employee to find out if there are any special concerns about cold or hot work areas.

If the settings seem reasonable and tampering persists, invest in good security devices.

Set Back HVAC During Unoccupied Periods
With most heating and air conditioning systems, there's no need to maintain normal operation at night, on weekends or during holidays.  If different departments keep their own hours, look into separate heating and cooling units, or zoned thermostats.

You can set back your thermostats manually, or use a clock thermostat, seven-day timer or energy management system to operate the system automatically.

The savings from an aggressive setback program can be impressive. An energy calculation for our area showed that a 14-hour night setback, and a full weekend setback from 65°F to 50°F, produced a fuel savings of 28 percent.

Turn On Later, Turn Off Earlier
You can further reduce your energy bills by lengthening the setback period. Adjust your HVAC controls to reach the desired temperature 30 minutes to an hour after your employees arrive.  When people have just come in from outside, the gradual warming or cooling won't be as noticeable.

At the end of the day, turn off equipment an hour before people leave. The temperatures inside your building shouldn't change quickly enough to affect comfort.

You can experiment to find out how long it takes your space to heat or cool, and for what period comfort can be maintained after you turn your system off.

Adjust Air Duct Registers
You can help balance the heating and cooling of your system by experimenting with the registers.  Open them fully far from the heating or cooling source, and close them part way near the central unit. You should find that temperatures are more even throughout the building.

Clean air filters Keeping air filters clean is akin to changing them in your car. For the best performance, do it regularly and often. Filters are cheap, and many experts recommend changing or cleaning once a month during the heating and cooling seasons.

The air will smell fresher, and by keeping particles out of your fans and motors, you can expect equipment to last far longer.

Clean Air Filters
Keeping air filters clean is akin to changing them in your car. For the best performance, do it regularly and often.  Filters are cheap, and many experts recommend changing or cleaning once a month during the heating and cooling seasons.

The air will smell fresher and by keeping particles out of your fans and motors, you can expect equipment to last far longer.

Moderate Projects

Save Energy in Unoccupied or Little-Used Areas
You may be able to turn off your HVAC system in certain areas: storage spaces, or parts of the building that are only used during a portion of the day.  You can do this if you have multiple zone controls, or separate units like window air conditioners. If there's a regular pattern of use in your building, you can install timers to control usage.

If you can't turn off parts of your heating or cooling system, consider these actions:

  • Have a zoned system with separate controls installed.
  • Cut off parts of your central system and replace them with window air conditioners and space heaters. This may also make your main HVAC system more efficient by eliminating long duct runs that often lose energy.
  • Revise your space plan. Move activities that require little energy to areas that are poorly served by your system.

Check Pipes and Radiators
All hot water pipes should be insulated with inexpensive foam or fiberglass tubing - which will save you about 50 cents per foot of pipe each heating season.  When you buy pipe insulation materials, be sure to specify that you want at least R3 or R4. R value measures a material's ability to reduce heat flow. The greater an R value, the better. (Note: If you have a steam system, use fiberglass to insulate your pipes. Steam pipes can get hot enough to melt foam.)

To keep your radiators working at top efficiency, clean them regularly and make sure they're not blocked by furniture or other objects.

Flat, dark colors are best for radiators, shiny silver paint is worst. Homemade aluminum foil screens placed behind your radiators will increase their performance by reflecting heat into the room.

Test, Clean and Adjust Your System
What if you could save 15 percent to 25 percent in one heating season, on a relatively small investment? 
In many cases, improving the efficiency of your heating system will only require a few inexpensive parts or minor adjustments.

However, since the efficiency ratings of certain types of oil or gas heating systems are 50 percent at best, big improvements from adjustments alone may not be possible.

If the technician testing your burner finds that this is the case, installing a new burner will usually pay for itself in a relatively short time.

Limit Exhaust Fan Use
When you use exhaust fans, stale air is replaced by fresh air that has to be warmed or cooled depending on the season.

Try to limit fan use if you can. For example, if your building has an exhaust system with so-called "make-up" air heaters, see if they can be wired to operate only when the exhaust fans are in use.

You can also wire bathroom exhaust fans to run only when the lights are on. (Be sure to check your local building codes before making any changes in the exhaust system.)

The only exception to this rule is the fan setting on your air conditioner(s). In many cases, it is more economical to run these fans continuously.

Make Use of Outside Air
If your building has windows that open, you can often cool it with fresh outside air.  In the evening, you can pre-cool your space in preparation for the next day's activity.

If you enjoy cool nights for a good portion of the summer, you should think about installing a large exhaust fan (usually in the roof or attic) to rid the building of accumulated heat.

Add Window Coverings
Window treatments can act as an insulating barrier.  For example, curtains, shades and blinds can be used to prevent heat loss at night, and to shield interior spaces from the sun's heat during the summer cooling season.

Reduce Ventilation
Unless your building is extremely tight, it is taking in a great deal of outside air around windows and doors, as well as through vents and other openings.  For this reason, there's a good chance that your mechanical ventilation system is taking in more air than necessary. As long as no symptoms of poor ventilation are present - stuffiness, accumulated smoke or odors - experiment to reduce the amount of air movement your system provides.

Start by adjusting dampers, changing control settings or fan speeds. On window air conditioning units, try to operate with the vent control in the "closed" position more often.

Be sure you're within the minimum ventilation guidelines for local building codes. You may want to contact a specialist to advise you in this area.

View Table 4 - Operating Hours of Air Conditioning Equipment

Inspect Ducts
Unless your building is extremely tight, it is taking in a great deal of outside air around windows and doors, as well as through vents and other openings.  For this reason, there's a good chance that your mechanical ventilation system is taking in more air than necessary. As long as no symptoms of poor ventilation are present - stuffiness, accumulated smoke or odors - experiment to reduce the amount of air movement your system provides.

Start by adjusting dampers, changing control settings or fan speeds. On window air conditioning units, try to operate with the vent control in the "closed" position more often.

Be sure you're within the minimum ventilation guidelines for local building codes. You may want to contact a specialist to advise you in this area.

Genuine Investments

Investigate Heat Recovery Technology
There are a number of systems on the market that allow businesses to reuse heat at less than the cost of producing it.  Air-to-air heat exchangers, for example, use exhaust air to preheat or precool incoming air depending on the season.

The technology is available to recover heat from flue gases, condenser water, hot water drains, solid waste, engine exhaust and lighting systems.

Energy Management Control Systems
Automated systems can be advantageous for a wide range of businesses, incorporating a variety of technology from programmable time clocks to fully integrated computer systems.

Year-Round Air Conditioning
Also consider year-round air conditioning. If you occupy a modern office building with large lighting systems or computer rooms, certain areas may require cooling even in the winter months. Consider separate air conditioning controls for these high heat zones.

When to Call an HVAC Expert
There are a number of things you can do to improve the overall efficiency of your heating and cooling equipment. They don’t necessarily cost a lot of money, but are complex enough to require the services of a specialist.

  • Add an automatic shut-off control to your boiler.
  • Replace an inefficient burner with a new, higher efficiency type-preferably with a variable firing rate.
  • Install an automatic flue damper.
  • Insulate boiler surfaces with removable fiberglass blankets.
  • Install turbulators to improve heat transfer and reduce stack temperature.
  • Install a multi-source heating system or heat pump to lessen your dependence on one type of fuel.
  • Install an automatic combustion control system if you have a large boiler.
  • Replace your old air conditioning system with a high-efficiency heat pump that will also save you heating dollars.
  • Install a high-efficiency heat pump in place of your outdated oil or gas furnace.
  • If possible, install air conditioning units on the north side of your building. Heat from the sun makes equipment work harder.
  • Install controls that automatically cut off sections of the system when not needed.
  • Insulate steam and hot water lines.
  • Modify equipment to return lost condensate to the boiler.
  • Simplify the system and eliminate unnecessary pipes.
  • Adjust to minimum acceptable flow rates. If you have a large system, using multiple pumps can allow you to vary the rate depending on the area served.
  • Replace old electric controls with preset solid state thermostats.
  • Control heating and cooling with separate thermostats or thermostats with two settings. Install automated controls to maintain proper temperatures in different zones.
  • Investigate load-shedding and peak-shaving controls to reduce your demand charges.
  • Increase outside air use by adding an economizer cycle with enthalpy control.
  • Install dampers in exhaust ducts.
  • Consider a variable air-volume/air-handling system.
  • Install automatic controls on the hot and cold decks.
  • Insulate all ducts and pipes (hot and cold).
  • Investigate heat recovery systems that reuse excess heat instead of venting it from the building.
  • Modify controls and ductwork to give you more flexibility in unoccupied areas.
  • Adjust the air temperature on handling units.
  • Raise the temperature of a chilled water central air conditioning system.
  • Lower the steam pressure or water temperature on a boiler.
  • Change fan speeds or belt drives in an air-handling system.
  • Turn off pumps in hot water heating systems during mild weather.
  • Clean the fins, tubes and coils of air conditioners or heat pumps.
  • Inspect the valves, dampers, linkages and motors of your equipment.
  • Maintain steam traps and vents in two-pipe steam heating units.
  • Check boiler insulation.
  • Repair cracks in boiler walls.
  • Fix, adjust or install new controls.
  • Repair vacuum systems in steam heating plants.
  • Shut off unneeded boilers.

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