It is important that a distribution system is
properly designed, installed and operated to ensure maximum energy efficiency
and comfort levels. Try to avoid placing any part of your distribution system
outside of your home’s insulation. This is sometimes done as a simple remedy to
a routing problem, but there is always some heat loss through the wall of any
distribution system. It is better that any losses heat (or cool) you rather than
your attic.
Registers in each room can be adjusted to control
the air flow. Return registers draw air from the rooms through separate ducts
back to the furnace to complete the cycle of air flow through the
house. Leaks in forced air distribution systems are
often ignored because they normally do not cause any obvious damage, but it is
important to avoid/eliminate such leaks. Leaks will affect a distribution
system’s ability to provide comfort in all areas of the house, and leaks in some
parts of the system can result in significant energy loss and/or
condensation-related damage which may be hidden from sight.
Distributes hot water from a boiler to radiators,
convectors or under-floor heating systems in each room. In older homes, large
cast-iron radiators are common. Modern systems feature smaller boilers, narrow
piping and compact radiators that can be regulated to provide temperature
control in each room. Under-the-floor heating systems can be built into the
floors of new and existing homes.
These have no central heating unit or distribution
system. Instead, individual space heaters – such as a wood stove, electric
baseboards, radiant heaters or heaters fueled with oil, natural gas or propane –
supply heat directly to the room. For safety, all space heaters except electric
ones need to be vented to the outside. An appropriately sized space heater can
supply some heat to all parts of a home if the design of the home allows for
natural distribution of heat from the heater location. In most cases, more than
one unit is required to comply with building code requirements, but multiple
units allow you to vary the temperature around the house.
Furnaces in forced air heating systems, boilers in
hot water systems, fireplaces and space heaters can be fueled by natural gas. It
is delivered to your house through an underground pipeline. (It is not available
in some areas.)
Most equipment fueled by propane is similar to that
fueled by natural gas. In many cases, the only differences are one or two small
components that can often be changed by a registered
contractor to convert a unit from one fuel to the
other. Propane is delivered by truck and stored in a tank on your
property.
Because of their similarities, natural gas and
propane heating equipment are discussed together. The term “gas” refers to both
natural gas and propane. The cost of the two fuels differs, so remember to check
for cost comparisons.
Some older furnaces and boilers, which are no
longer produced but are still in use, require a continuous liner in a masonry
chimney or a metal “B” vent chimney. The liner is needed because the combustion
gases contain water vapor which condenses on masonry and causes deterioration
over time. About 35 per cent of the heat from the fuel goes up the chimney with
these models.
These models remove more heat from combustion gases
so that less heat escapes when the gases are exhausted and efficiency is
improved. Depending on the circumstances, they might be vented through a wall or
through a chimney.
These models extract so much heat from combustion
gases in order to achieve their efficiency, that they can be safely vented
through a narrow plastic pipe that runs through the
wall.
Gas-fueled
fireplaces
Gas fireplaces are sometimes used to provide space
heating, though they are often chosen for aesthetic reasons. There can be
significant differences in energy efficiency from one model
to another, and the effective efficiency of some
types can be significantly affected by how they are used.
Oil furnaces and boilers have a burner, a heat
exchanger and a blower or pump. Oil is delivered by truck and stored in a tank,
which is usually located in the basement.
Older, conventional oil furnaces and boilers with a
standard burner have a seasonal efficiency generally ranging from 60 to 70%.
Like older, conventional gas furnaces and boilers, they are no longer produced.
However, in an existing model that is working well, the seasonal efficiency can
be improved by replacing the burner with a flame retention unit – usually a more
cost-effective step than replacing the entire furnace.
A typical new oil furnace or boiler has a seasonal
efficiency rating generally ranging from 78 to 86 per cent. Many of these units
can be vented through the wall.
There are free-standing oil space heaters with a
visible flame now available. There are no efficiency standards for these
products.
Electricity
Electric resistance systems can consist of a
central furnace or boiler connected to an air or hot water distribution system,
radiant panels embedded in the floor or ceiling or a baseboard space heating
system. Electricity also powers heat pumps. When electric resistance heating is
used in a new home, including as a back-up for an air source heat pump, the
building code requires
the house to be built with higher minimum levels of
insulation.
Heat pumps
A heat pump is usually an electrically-powered
system that can either heat or cool by transferring heat from one place to
another. During the heating season, a heat pump extracts heat from
either the air, ground or water outside the house,
and transfers it indoors. In the summer the direction of the heat flow is
reversed, extracting heat from indoors and transferring it outdoors,
to
provide air conditioning. Because they satisfy a
substantial part of your heating needs by utilizing already available heat,
rather than consuming electricity to generate all of the heat you
need,
heat pumps are significantly more efficient than
electric resistance heating.
There are three main types of heat pumps:
- air source heat pumps
- earth energy
systems
- bivalent heat pumps.
Air source heat pumps
These most commonly-used heat pumps can provide all
the cooling requirements of a home and most of the heating needs, but they
require an auxiliary heating source during very cold weather. This can be either
an electric resistance or a fossil fuel unit.
Earth energy systems
Also known as ground source heat pumps, these
systems transfer heat from the ground, ground water or surface water and use it
to provide home heating. For summer cooling, the process is reversed. If
desired, earth energy systems can be equipped to provide domestic hot water year
round. Electric resistance heaters may be installed to provide supplementary
heating for the
coldest days.They normally utilize much less
electric resistance heat and offer significantly higher efficiency than air
source heat pumps.
Wood
Some households use wood as their main fuel but
even more use it as a supplementary source of heat. Most of these households are
outside large urban areas where firewood is usually less expensive than other
fuels. The most common approach to wood heating today is a wood stove or
high-efficiency fireplace installed in the main living area of the house. If the
house is
medium-sized and relatively new, this kind of
equipment can provide almost all the heat needed.
If you have an existing masonry fireplace, a
high-efficiency fireplace insert could be a good option. And many models offer
the pleasure of a visible wood fire.
Older or larger houses may need the additional
heating power offered by a wood-burning furnace. If your present heating system
is a forced air furnace that uses a more costly fuel, you might want to consider
an add-on wood furnace. It is installed beside the existing furnace and the duct
work is modified so that it can be shared by both furnaces. Combination wood/oil
or wood/electric furnaces are options for new or replacement systems. Stoves
that burn pellets made from wood or agricultural crops such as corn kernels are
also available. Pellets are automatically fed into the burner and the
householder simply dials in the required temperature on the
thermostat.
When shopping for wood-burning equipment, visit
several wood heat retail stores and discuss appliance selection, location and
installation with a knowledgeable salesperson.Always buy wood-burning equipment
that is certified for safety. It is
also preferable to buy equipment that has been certified
as meeting the U.S. Environmental Protection
Agency (EPA) or Canadian CSA-B415 emission standards.
These certified wood-burning appliances produce one-tenth of the
chimney emissions and one-third higher efficiency than earlier
units.
Outdoor furnace
“Outdoor” wood furnaces or boilers are also on the
market. They may appear attractive, because they will burn low cost material you
would not think of putting in an indoor appliance and can burn for long periods
between refueling. However, they can be low on efficiency and high on emissions.
Solar energy
Like wood, solar energy is a renewable resource.
Solar heating does not involve the combustion of fuels, so it does not produce
environmentally-harmful emissions. It can be as simple as south facing windows
serving as passive solar collectors. Passive solar heating is free and should be
an important consideration in the design of homes. Homes built to high levels of
energy efficiency and designed to make the most use of free solar heating can
save hundreds of dollars a year on energy bills.
Other energy sources
Residential systems are available to generate
electricity from sunlight or wind. In certain situations, such as remote
locations, one of these may be the most practical option. In addition, the
government is establishing standardized processes and technical requirements
which will require electricity distributors to allow customers with qualifying
generation equipment to supplement their utility electricity needs with power
they generate themselves.
Cooling Systems (air
conditioning)
Two types of units cool an entire house: a central
air conditioner or a heat pump. If you only need to cool a specific area, a
window air conditioning unit could be your most energy-conserving choice.
Regardless of what type you are considering, remember that models will vary in
efficiency ratings and efficiency has a direct impact on operating costs, so
optimizing efficiency should be a priority. Consider buying an ENERGY
STAR®-qualified model.
Central cooling
If you decide you want to cool your entire house,
you should consider which system to install – central air conditioning or a heat
pump – when reviewing your home’s heating needs. An air conditioner is actually
a heat pump that can only cool. *Remember: your heating decisions can affect
your cooling options.
Duct work for central
air
Duct work is generally needed to carry cool air
throughout the house in a central air conditioning system. If you have a forced
air heating system you can usually use the same ducts for cooling. If you do not
have duct work, you can look into installing it or consider air conditioning
technologies that have been developed for homes without ducts. These
alternatives are more costly, so if you are considering them, investigate your
options with your heating/cooling contractor.
Mini splits
Mini splits are systems suited to homes without a
central air-distribution system. No duct work is required. The system consists
of two components: an outdoor condensing unit, and an indoor evaporator and fan.
The indoor section can frequently be mounted on any interior or exterior wall,
and is much quieter than a window unit.
Window units
Window air conditioners are effective if you only
need to cool a specific area of your home. They will cost less to install than a
central air conditioning system. If you don’t have duct work, they might be your
most practical choice. It is important to match the capacity of the window air
conditioner with the size of the area to be cooled. Window units should either
be covered in winter or, better still, removed to minimize heat
loss.
Other Ways to Cool Your
House
The following measures will help keep your home
more comfortable:
- Install ceiling fans
to circulate air.
- If you’re planning for the long term, plant trees that lose their
leaves in the fall on the east, south
and west side of your house.
- Close the drapes or blinds on south and west-facing windows during
sunny summer days to reduce heat gains.
- Turn off lights and appliances when they are not in use.
- Install awnings for patio doors and windows that face the sun.
- Open windows in the evening and at night during the summer
months.
Hot Water and How to Heat
It
There are several water-heating
options available to you. While you are taking steps to save on home heating,
don’t forget to see what you can do to lower your water heating costs. Check
with your fuel supplier for more information, and consider alternatives to your
current method.
Storage-type water
heaters
Most homes have storage-type water heaters in which
water in a tank is heated by a gas or oil burner or by electric elements.
Traditional storage heaters have been improved with such features as
through-the-wall venting for combustion units and better insulation, making them
less expensive to operate. Units designed to give even greater efficiency are
now available.
Instantaneous water
heaters
Instantaneous water heaters which heat water as
needed and have no storage tank are available, but not widely. They require
little space, but they usually cost more than storage-type water heaters and
more than one unit might be required to meet your needs. For electric
instantaneous water heaters, upgraded wiring is often necessary.
Integrated (combination) hot water
systems
Systems that combine space heating and water
heating are becoming more popular. Water can be heated with a boiler or a
storage-tank water heater. The hot water can be used for space heating as well
as domestic hot water needs. Space heating methods include baseboard radiators,
in-floor radiant heating and forced air heating when piped to an air handler.
Some of these systems can also be used for pool and spa heating and snow-melting
applications. Combo systems vary widely in efficiency and must be carefully
designed to give satisfactory service.
Solar water heaters
In solar water heaters, energy from the sun is
collected by solar panels and transferred by circulating fluids to a storage
tank. These heaters are typically used with an electric water heater, or one
fueled by oil, natural gas or propane, which acts as a back-up for overcast
days. Solar collector panels can be mounted on any unobstructed roof, wall or
ground frame that faces between
southeast and southwest. Solar water heaters are
designed to provide between 35 and 75% of your hot water needs, with the back-up
providing the balance.
Replacing Your System
Review your options, consider the pros and cons of
different equipment and fuels, and compare installation and operating costs. Now
get ready to improve your existing system, and it’s time to select a contractor.
Here are some tips:
- Look for a registered
contractor
Your contractor will supply
and install your equipment. Proper
installation is essential for the safe, efficient and
economical operation of your system.
Electric equipment must be installed by a licensed electrician and all electrical work must be
inspected.
- Get estimates from several
contractors.
Prices can vary significantly among contractors.
Ask each firm for a written estimate covering the following items:
- The total cost and a listing of all necessary
work including improvements to the existing
system and the provision of combustion air if
applicable
- Heat loss/gain analysis
- The size and seasonal efficiency of the
unit, and sound ratings if applicable
- Responsibility of the contractor or
homeowner for:
- Obtaining permits and paying related fees
- Removing and disposing of old
equipment
- Arranging for such work as
installation of gas supply
- Arranging necessary inspections
- A work schedule and completion date
- Guarantees, warranties and service contracts
- Terms of payment
- Evidence of an
electrician’s licence as appropriate
Use costs (both installed and operating), work
schedule, warranties and service as the basis for your decision. Ask the
contractors you are considering for references, and follow up by contacting
previous customers. Ask what they think about the contractor, fuel supplier and
the options you are considering.
- Choose the right equipment
In order to correctly size new heating and cooling
equipment, your contractor must analyze how much heat is lost from your home in
winter and gained in summer. Ask for this heat loss/gain analysis in writing,
including the method used to perform the calculation. This calculation should
take into consideration such factors as the size of the house, its level of
insulation and the condition of windows and doors. If the heat loss and gain is
significant and you haven’t already taken steps to increase the energy
efficiency of the house, now is the time to do it.
Avoid the temptation to simply choose the same size
equipment that already exists in your house without doing a heat loss/gain
analysis. Your home has likely been altered over the years
and the system might even have been the wrong size
at the start. An oversized unit will usually operate below peak efficiency, and
both oversized and undersized units can adversely affect the
comfort of your home. Any installation involving
combustion equipment should include steps to ensure that there will be an
adequate supply of air for combustion and venting, and that other air exhausting
equipment will not cause problems.
Changing Your Water
Heater
Size is an important consideration when selecting
new hot water equipment. A larger family is likely to use more hot water. A
“downsized” household – for example, an older couple whose children have grown
up and moved into their own homes – will no longer need a water heater meant to
supply the needs of four or more people. By practicing water conservation – for
example, by installing energy-efficient showerheads and aerators on taps and
using cold water in your washing machine – you can substantially reduce your hot
water usage.
Steps to installing a hot water
tank
Contact your local fuel supplier or contractor and
ask for the efficiency ratings of the models you are considering. When you have
selected a unit just big enough to meet your household needs, your fuel supplier
or contractor can arrange for a qualified serviceperson to install the water
heater. If you have an electric hot water tank, wrap it in an insulating
blanket. Make sure the blanket is certified for use on your heater and is
properly installed. Insulate both the hot and cold water lines of the tank and
consider installing a heat trap. Be careful not to insulate the pipes too close
to the flue of a fossil-fueled tank. Ask your fuel supplier about any water
heating cost-saving programs they offer. Some suppliers do some of the work at
little or no cost to you.
Glossary of terms
Here is a quick overview of terms used in this
guide and that you’ll need to know as you gather information about your home
heating and cooling options.
AIR SOURCE HEAT PUMP
A heating-cooling unit that transfers heat in
either direction between the air outside a home and the indoors.
AIR SUPPLY FOR
COMBUSTION
The air that a furnace, boiler or space heater
requires to burn fuel.
AQUASTAT
A thermostat that controls the water temperature in
a boiler.
BOILER
The heating unit used with a hot water (hydronic)
distribution system.
CENTRAL AIR
CONDITIONER
A unit that cools an entire house by removing heat
from the inside air and releasing it outside.
CONTROLS
Devices such as a thermostat that regulate a
heating or cooling system.
CONVENTIONAL GAS FURNACE OR
BOILER
A gas heating unit with an annual fuel utilization
efficiency (AFUE) less than 70%. It exhausts through a masonry chimney (which
should be lined) or metal “B” vent.
COST-EFFECTIVE HEATING/COOLING
SYSTEM
One that produces good value for money after all
costs (purchase, installation, financing and energy charges) are
considered.
DISTRIBUTION SYSTEM
The components of a heating or cooling system that
deliver warmed or cooled air, or warmed water, to the living space.
DOMESTIC HOT WATER
Hot water used for household purposes.
EARTH ENERGY SYSTEM (ground source
heat pump)
A heat pump that transfers heat from the earth or
ground water in cold weather and transfers it to the house through an
underground piping system for space heating, cooling or water heating. The
process reverses in warm weather, and heat is discharged to the ground or
water.
ELECTRICAL RESISTANCE
HEATING
Heat produced by passing electricity through a
resistor.
FLAME RETENTION HEAD
BURNER
A higher-efficiency burner in an oil furnace. It
produces a hotter flame and operates with a lower air flow, thus reducing heat
loss up the chimney.
FLUOROCARBON
REFRIGERANTS
The fluids commonly used in refrigerating and air
conditioning equipment to create the cooling effect. These fluids can damage the
environment.
FORCED AIR
A distribution system in which a fan circulates air
from the heating or cooling unit to the rooms through a network of
ducts.
FOSSIL FUEL
A naturally occurring carbon or hydrocarbon fuel
such as natural gas, propane and oil, formed by the decomposition of prehistoric
organisms.
FURNACE
A heating unit that uses a forced air distribution
system.
GROUND SOURCE HEAT
PUMP
Another term for an Earth Energy
System.
HEAT EXCHANGER
A structure that transfers heat from one gas or
liquid to another gas or liquid. For example, the hot combustion gases in a
furnace to the circulating household air or, in a boiler, to the circulating hot
water.
HEAT RECOVERY VENTILATOR
(HRV)
A device used in central ventilation systems to
reduce the amount of heat that is lost as household air is replaced with outside
air. As fresh air enters the house, it passes through a heat exchanger heated by
the warm outgoing air stream and is preheated.
HIGH-EFFICIENCY (condensing) FURNACE OR
BOILER
A heating unit with an annual fuel utilization
efficiency (AFUE) of 90% or more. It has a second stainless steel heat exchanger
that removes additional heat from exhaust gases. Water vapor condenses as the
exhaust cools. The unit vents through a narrow plastic wall pipe instead of a
chimney.
HYDRONIC SYSTEM
A distribution system in which hot water is
circulated through a network of pipes to radiators, wall panels or an
under-floor heating system.
INSTALLED COST
The total of the purchase price and the
installation costs of equipment.
INSTANTANEOUS WATER
HEATER
A device that heats water as required but does not
store it. The unit is usually located near the point of use.
INTEGRATED (combo) HOT WATER
SYSTEM
A system that provides both space and water heating
from a single heat source.
KILOWATT
A unit of electrical power used to measure the
heating capacity of electric equipment. One kilowatt (kW) equals 1,000 watts
(W).
MID-EFFICIENCY NATURAL GAS OR PROPANE FURNACE OR BOILER
A gas heating unit with an annual fuel utilization
efficiency (AFUE) of 78 to 82%. Some models exhaust
through the basement wall.
NEW OIL FURNACE
Efficiencies (AFUE) range from 78 to 86%. Has flue
gases that may be exhausted through a chimney or a side wall vent.
R-2000
A performance standard for new homes under a
voluntary government/industry program. Builders meet the standard by offering an
integrated package of features designed to meet the R-2000 requirements. The
package includes high insulation levels, air-tightness, heat recovery
ventilation and efficient heating/cooling systems.
RETROFIT
Replacement of one or more components of an
existing system.
SEASONAL EFFICIENCY
A performance rating that considers the heat (or
‘cool’) actually delivered to the living space, the total energy available in
the fuel consumed, and the impact the equipment itself has on the total heating
or cooling load through an entire heating or cooling season. HSPF, AFUE, SEER
and EF are seasonal efficiency ratings.
SEER
seasonal energy efficiency ratio
SETBACK THERMOSTAT
A programmable thermostat with a built-in timer.
You can adjust it to vary household temperature automatically.
SPACE HEATER
A heating unit that supplies heat directly to the
room where it is located and is not connected to a distribution
system.
STORAGE-TYPE WATER
HEATER
A tank that heats and stores hot
water.
TON
A measure of the cooling capacity for central air
conditioners and heat pumps.
Efficiency Ratings: AFUE, COP, HSPF, SEER
& EER
Take a few moments to familiarize yourself with the
efficiency ratings you’ll find on various pieces of equipment.
Boilers and Furnaces
Rating to look for: AFUE
The annual fuel utilization efficiency (AFUE) of
furnaces and boilers measures their performance over a typical heating season.
It takes into account things like on-and-off cycles and heat loss through the
chimney or vent, and is the most useful furnace and boiler rating available. The
higher the rating, the more efficient the unit.
There is a second efficiency rating for furnaces
and boilers and it is known as steady-state efficiency. It is higher than an
AFUE rating but it’s not as helpful. It measures the equipment’s performance
after it has been running a short while and all components have reached their
normal operating temperature. The steady state efficiency of furnaces and
boilers is determined by
comparing the amount of heat that’s available in
the fuel to the amount that is converted into usable heat, but it does not
include off-cycle losses.
Wood-burning
appliances
Advanced equipment which is certified as meeting
the EPA or CSA-B415 emissions standard normally exceeds 60% and averages 70%
efficiency. Conventional wood-burning appliances which are not certified as low
emission average 50% efficiency, with a range of 35 - 70%. Although some wood
burning equipment is specifically certified for efficiency, most is
not.
Also, most wood-burning appliances are manually
operated, not automatic, and so the practices of the operator will affect the
efficiency actually achieved.
Heat pumps
Ratings to look for: COP, HSPF
Earth energy systems are rated for heating
efficiency by comparing them to electric resistance heat. The measurement used
is called the coefficient of performance – COP – and is determined by dividing
the heat output by the energy input. Since the COP of an electric resistance
heater is 1.0 – which means that the same amount of energy that goes into it as
electricity comes out as heat – any rating higher than 1.0 means that for the
same amount of electricity going in, more heat comes out. Look for a COP of 3.1
or more.
The heating efficiency rating for an air source
heat pump is called the heating seasonal performance factor (HSPF). This is
determined by dividing the total heat provided during the season (in BTU) by the
total energy consumed by the system (in watt-hours). The higher the rating, the
more efficient the heat pump is over the entire heating season. Look for an HSPF
of more than 5.9.
Air conditioners and air source heat
pumps
Ratings to look for: SEER
A SEER rating, which stands for Seasonal Energy
Efficiency Ratio, tells you the cooling energy efficiency of air conditioners
and air source heat pumps. The rating is determined by dividing the total
cooling provided during the season (in BTU) by the total energy consumed by the
system (in watt-hours). The higher the rating, the more energy-efficient the
unit. SEERs for new central air conditioners and air source heat pumps currently
range from 10 to 17. For room air conditioners, the range is 8 to
12.
Earth energy systems
Ratings to look for: EER
If you want to know how efficiently an earth energy
system can cool, look for the letters EER, which stand for energy efficiency
ratio. EER ratings are determined by dividing the cooling output of the ground
or water source heat pump (in BTU/hour) by the power input (in watts). Look for
an EER of at least 10.5.
Hot water equipment
Storage-type Hot Water Heaters
An energy factor (EF) is used to rate the energy
efficiency of storage-type hot water heaters. Both on-cycle efficiency and
off-cycle losses are taken into account, which makes it a seasonal rating. The
higher the EF, the more efficient the unit. You can expect the following energy
factor ranges for new storage-type water heaters:
- Gas 0.56 to 0.86
- Electric 0.87 to 0.98
- Oil 0.53 to .68
A storage-type water heater added to an earth
energy system will normally have an energy factor of 2.7 to 3.1.
