How important is the sizing of my air conditioning system?
Correct sizing of the air conditioning system is critical for both comfort
and efficiency. A system that is oversized will sacrifice both comfort and
efficiency. The same can be said for an undersized unit.
Before purchasing an air conditioning system, make sure a licensed technician
performs a load calculation on your home to ensure proper sizing. Reliant
Energy recommends a minimum of 14.00 seasonal energy efficiency ratio
(SEER).
What is the best way to cool the upstairs of a home?
There are several ways to help cool a home’s upstairs. Most of these
solutions involve hiring a registered heating, ventilation and air conditioning
technician to diagnose the problem.
• The air distribution system must be sealed, sized and insulated properly.
These factors working together have a big effect on your comfort level
upstairs. If the ductwork to certain rooms upstairs is not large enough, then
not enough air may be available to meet the heat load of the room. A
room-by-room load calculation can help determine the exact number of BTUs
(cooling units) needed per room.
• An undersized air conditioning system will continuously run without
properly cooling your home.
• Have your ductwork checked. Ducts on your supply system may be
disconnected, crushed or crimped, which would prevent air from being
distributed effectively throughout the upstairs.
• The return air system may be grossly undersized.
• If your home is more than 20 years old, you may need more attic
insulation.
• Add window coverings to help block the sun. Curtains, blinds and solar
screens can go a long way toward reducing the solar heat entering your
home.
How can I decrease my summertime energy usage if I’m away from home during the day?
Lowering your energy usage is directly related to lowering the setting on
your air conditioner’s thermostat. We recommend a thermostat setting of 78° F.
For every degree below 78° F, your cooling costs may increase up to 5-7%. When
you leave for work, raise your thermostat to around 81 to 82° F. Also, make
sure that you replace your air conditioning filters on a monthly basis. Closing
your curtains and/or blinds during the day can also prevent solar heat gain
from warming up your home.
I live in an apartment. Would a programmable thermostat be a wise investment?
Yes. You will see energy savings by installing a programmable thermostat in
your apartment. Set and program the thermostat to fit both your lifestyle and
work schedule. Before purchasing a programmable thermostat, check with your
apartment manager to see if they allow tenants to install them. Also find out
the type of heat your units use — electric strip heating, heat pumps or
hydronic. This information is necessary to find the right programmable
thermostat.
I plan to be away from home for about two weeks this summer. Can I turn my air conditioner off while I'm gone?
To ensure the removal of moisture/humidity from your home, we recommend
setting your thermostat to 82° F. It is best never to turn your air conditioner
off when experiencing humid weather.
Is it a good idea to use the air conditioner in fan mode on cooler days — when it is warm inside, but cooler outside?
The motor blower fan that operates your air conditioning and heating system
can cost anywhere from $30 to $75 per month when operating 24 hours a day, 7
days a week. We recommend not placing the fan in the ‘on’ position because it
will result in increased energy usage and minimal comfort gain. It is best to
open a window and turn on a ceiling fan when weather permits. In addition, the
temperature in your attic may be higher because of radiant heat gain. And, your
ductwork could be acting as a heat exchanger, transferring heat into your
home.
What is the best type of attic insulation material?
Reliant Energy does not recommend one type of insulation material over
another. Here is some information about the different insulation
materials:
Cellulose insulation
Cellulose is essentially newspaper and cardboard that has been shredded. It is
organic and porous, which means it does a great job of trapping air. Its
insulation properties seem to last longer than other products, because it
doesn’t settle as quickly. It’s also treated with Boric acid, which provides a
level of fire retardation and helps repel insects and bugs.
Batt or blown insulation
Loose insulation is good as long as it is applied evenly throughout your attic.
Blown insulation reaches cracks and crevices that batt insulation may miss.
Should I leave my ceiling fans on when I’m away from home?
From ceiling fans to box fans, all fans are made for people — not rooms.
Fans do not lower a room’s temperature, they just make people feel cooler
because they cause a wind-chill effect. Even though fans cost only a penny per
hour to operate, it’s best to turn them off when you leave the room or
house.
Which way should a ceiling fan rotate in hot weather and which way in cool?
Most ceiling fans are reversible. If you have a switch on the bottom of your
fan, that means your fan is reversible. In the winter, it is best to direct the
air flow upward — in a counter-clockwise rotation. This can be accomplished by
placing the fan’s switch in the top position. The reason for this direction is
that for comfort, it is best to prevent the hotter air from collecting at the
top of the ceiling. The fan will draw cold air from the bottom of the room and
force it upward, mixing with the hotter air. The air will then be pushed down
the sides of the room into the living zone, making the room feel warmer.
In the summer, the switch should be in the down position — in a clockwise
rotation. This will push the air downward, causing a wind-chill effect.
What is the most energy-efficient setting for my heater?
In the winter months, it’s best to set your thermostat to 70° F or lower.
Each degree above 70° F can increase your heating costs by as much as 3-5% per
degree.
Are electric furnaces energy efficient?
Electric furnaces are expensive to operate compared to other heating choices
and have a life expectancy of anywhere from 10 to 30 years. A thermostat
controls the electric furnace and uses heat strips and an air handling system
to supply heat to the home.
What is the most energy-efficient way to heat a home?
Our top recommendation for heating your home is with a natural gas furnace.
If natural gas is available, we recommend a gas furnace with an Annual Fuel
Utilization Efficiency (AFUE) of 80% or higher. Operating costs for a gas
furnace are relatively low and are comparable to an electric heat pump. If the
gas furnace is located in a room below the ceiling insulation, be sure to
provide proper venting through a ducted opening to the outside.
How can I increase the energy efficiency of my home?
Reliant Energy customers can visit the Energy Savings Center and take
the Reliant Energy Checkup for energy-saving
information tailored to your home.
How can I assess the energy efficiency of my home?
To find ways to save tailored to your home energy use, use our online Reliant Energy Checkup Tool. You can also request a Home Energy Checkup, in which one of our energy experts will evaluate your home and provide customized solutions to help you lower your usage.
How much of my home’s energy usage can be attributed to lighting?
Lighting accounts for about 7% of your home’s total energy usage. It makes
sense to ensure that you’re using the most energy-efficient lighting available.
Learn more
about energy-efficient lighting.
Are radiant barriers effective in keeping the heat out?
Radiant barriers do an excellent job of preventing radiant heat from
entering your attic and may lower your attic’s ambient temperature up to 35
degrees. In addition, radiant barriers may enhance the comfort of your home,
because they block out heat gain into air conditioned space. Your exact energy
savings will vary greatly, depending on such factors as the efficiency of your
air conditioning system, your current insulation levels and the efficiency of
your air distribution system. Learn more
about radiant barriers.
I'm in the market for a stand-alone storage freezer. Can you tell me which is the most energy-efficient model?
All new model freezers are energy efficient, thanks to legislation passed in
the early 1990s. Manufacturers now must meet strict Federal guidelines to build
energy-efficient freezers.
See more energy-saving tips about freezers.
No. A study conducted in Houston by the National Bureau of Standards found
that power vents are not a cost-effective investment. Although there was some
savings in air conditioning costs, the savings was smaller than the energy
required to keep the power vents operating. Ridge vents — teamed with
continuous soffits — are the best way to ventilate an attic. The key to a
ventilation system is air flow.
Are ridge vent systems effective in reducing energy usage?
Yes. Reliant Energy strongly recommends passive ventilation systems and
believes that ridge vents — coupled with continuous soffits — are the best way
to ventilate an attic. The key to a good ventilation system is air flow.
I need a new water heater. How do I properly size a new water heater, and what ratings should I look for?
Gas water heaters typically come in 40, 50, 75 and 100 gallons for
residential applications. As you increase the volume of the gas water heater,
you also increase the surface area—leading to increased energy usage. By
upgrading to low-flow showerheads and faucets, you can sometimes use a lower
gallon water heater. Learn more about water heaters.
Regarding energy ratings, be sure to compare the black and yellow Energy Guide
labels for same-capacity water heaters. When looking for a contractor, make
sure they are bonded, insured and have some level of training from the
manufacturer.
Are European instantaneous water heaters more energy efficient than conventional water heaters?
These water heaters are not energy efficient and are only appropriate for
small applications. Instantaneous water heaters are tankless units that heat
the water only as needed at the end source. The water is heated by a high-power
electric heating element as the water flows through the unit. Even though these
water heaters are popular in Europe, they have not gained popularity in the
United States.
Can I use an insulation jacket around my gas water heater?
No. You should not use an insulation jacket on a gas water heater unless the
manufacturer specifies that it is safe to do so. Most of the time, insulation
jackets are used on older, inefficient electric heaters. If the insulation
jacket should slip or come off of the gas water heater, it could pose a fire
hazard due to the pilot light. Be sure to read all manufacturer’s labels — your
heater may already be insulated on the inside.
Does the building code require double-pane low-E windows?
You will need to contact the permitting jurisdiction in the area in which
you are building to find out if double-pane low-E windows are required. This
would be either the county—if you are building in an unincorporated area—or the
city if you are within the municipality. Double-pane low E windows may be
required for builders participating in the EPA’s Energy Star program to certify
their homes. In addition, this certification may supersede any local building
codes. Even though they cost more than single-pane windows, double pane low-E
windows will decrease your energy usage while enhancing the comfort of your
home.
Are solar screens effective in reducing my energy usage?
Yes. The addition of solar screens can reduce your energy usage and increase
the comfort of your home. We recommend targeting the east- and west-facing
windows of your home, because this is where most solar heat gain occurs.