About Your House
Energy Efficient Upgrade - Mechanical Systems
One of the best ways to make your home more comfortable,
healthier and less expensive to operate is to upgrade the
heating, cooling and ventilation systems. Energy efficient
equipment upgrades can be expensive, but can be offset by
lower operating costs.
Before you decide to upgrade mechanical equipment, it’s
also critical to understand how the overall performance of the
house will be affected. Keep in mind that your lifestyle, the
number of occupants, their age, the climate and the insulation
levels of the house all have an impact on the performance of
mechanical systems. This type of upgrade will require
professionals to do it right and to avoid causing other
problems in the house. It’s important to weigh the benefits
against the costs.
All equipment has an optimal life span. Older furnaces and
boilers may need replacing simply because they have outlived
their useful life, or because they may not have been regularly
If you have noticed a sudden change in fuel bills, it may
be because you have started using the house differently —
perhaps the temperature settings have been increased because a
new child has entered your life or an elderly person has moved
Older homes often have areas that are cold because of
poorly laid out heating and mechanical systems.
Perhaps you are undertaking other renovation work that
requires some adjustments to your present mechanical systems.
In this case, you can also consider upgrading your mechanical
equipment to take advantage of new, more efficient products.
This may also be an opportunity to install a proper
ventilation system where one does not exist.
It is important to note that mechanical systems must not
change the balance between the air pressure inside and outside
the house — since high pressure differences can lead to
combustion spillage problems from furnaces, hot water heaters
or fireplaces. If there are no fuel burning appliances of any
kind in the house, then this is not a significant issue.
Renovating is an ideal time to make your house healthier
for you, the community and the environment. When assessing
your renovation project, be sure to consider the five
essentials of Healthy
House as a System
A house is much more than just four walls and a roof — it’s
an interactive system made up of many components including the
basic structure, heating, ventilating and air conditioning
(HVAC) equipment, the external environment and the occupants.
Each component influences the performance of the entire
system. A renovation provides an opportunity to improve how
your house performs.
Energy efficient mechanical systems such as gas furnaces,
usually have a sealed combustion chamber that isolates the
flue gases from the house. Direct vent gas fireplaces can be a
decorative heat source too, while not compromising the indoor
air quality. New appliances may require special provisions for
make-up air if the combustion appliances are not the “sealed
combustion” or “induced draft” type.
Knowing the properties and operating characteristics of
your heating system will help you to determine the changes you
may want to consider. You will want to hire a professional
heating contractor to make changes in the mechanical systems.
Thinking about what changes you’d like to make or anticipating
problems ahead of time will help the heating contractor
address the shortcomings of your home’s system. Here are some
of the likely situations that people encounter.
- How old is the furnace or boiler? Is it more than
15 years old?
- When was the last maintenance service done?
- Replace the furnace, depending on its age and
condition. Furnaces typically last 15 to 20 years,
while boilers may last up to 40 years if maintained
- Older furnaces have very inefficient motors and
the heat exchangers are not as efficient at extracting
heat compared with newer furnaces. Hot water based
heating systems may have inefficient boilers and
pumps. New equipment is much more energy efficient
than the older equipment likely to be in your home.
- Have your heating system maintained regularly to
keep it operating safely and efficiently. Filters must
be cleaned or replaced regularly. Combustion system
components must be maintained as outlined in user
- Choose more energy efficient appliances that may
make it possible to eliminate existing chimneys. This
is worth considering if the chimney is located on an
exterior wall or mostly outside. These types of
chimneys can contribute to backdrafting of combustion
- Inadequate maintenance will mean a shorter life
span for the equipment and can lead to premature
failure, incomplete combustion of fuels and
backdrafting of combustion gasses. Clogged filters and
flues are a fire hazard. Cracked heat exchangers allow
combustion gases into the home’s air.
- Newer, combustion-fuelled, energy efficient
equipment requires venting and combustion air supply
directly to the unit. This may also have an impact on
the overall environment within the house.
- Many new furnaces, because they are significantly
more efficient, may require some modifications to the
original heating ducts.
- If only one appliance is upgraded and removed from
a flue, then there may have to be modifications made
to the chimney so that the remaining appliance is
- Is the house warm enough?
- Is it easy to keep the house at a uniform
- Replace old thermostats with programmable models.
New thermostats that can automatically setback
temperature settings can result in energy savings.
- Improve cold air returns to increase the capacity
of the system to deliver adequate airflows.
- Consider draftproofing and insulation upgrades to
reduce the heating load.
- Choose a new, more efficient heater that will
likely be much smaller.
- The furnace may operate inefficiently. Furnaces
that frequently turn on and off (excessive cycling)
can deteriorate prematurely, along with the flue. This
may happen if your furnace is oversized.
- Are there areas that are difficult to keep warm?
- Check to make sure that dampers and valves are
open and registers and cold air returns are not
blocked by furniture. It may be necessary to install
balancing dampers to divert heat away from areas that
receive too much heat to rooms that are too cool.
- Upgrade or replace circulation pumps in hydronic
heating systems with individual zones.
- Install pumps or fans in older gravity systems.
- Prolonged periods of low temperatures will create
uncomfortable conditions. There will also be increased
relative humidity in those areas, so that condensation
may take place on cold surfaces. Wet surfaces are
ideal for mold and fungus growth, compromising indoor
- Warm air ducts that run through unheated spaces
need to be sealed with duct sealers and insulated; hot
water pipes need to be insulated.
- Is there enough fresh air in the house?
- Do smells linger? If you burn breakfast toast, can
you still smell it at lunch time?
- Install a proper mechanical ventilation system to
provide adequate air exchange. The system must have a
fan capable of operation for long periods. This may
mean a fan that runs continuously or at least for many
hours per day. Opening windows does not provide
adequate air exchange, even if weather conditions are
- Choose a heat recovery ventilator to provide
controlled, fresh air, while conserving heat in the
winter for optimum energy efficiency.
- Poor indoor air quality can compromise health. If
those smells are a result of combustion, such as
lingering smells from a fireplace, wood or oil stove,
then it may mean that the appliances are not operating
properly and may be a health and safety risk.
- Would it make sense to switch to natural gas?
- How hard will it be to install the new fuel
- Consider whether you will really save money by
switching fuels. Your heater must convert the fuel
energy efficiently to save you money.
- Consider maintenance costs.
- Factor in the cost and inconvenience of switching
fuel. If you switch from electricity or oil to natural
gas, you will need to install a natural gas feed from
the service to the house. This will mean digging a
trench. If there are extensive rock outcroppings or
large hard surfaces in the yard, it may add to the
cost of installation.
- In most cases, there will be a limited range of
upgrading options and you will likely remain with the
fuel you are now using. Fuel choice should be made on
the basis of availability, fuel and installation cost
and availability of service tradespeople to install
and maintain the equipment.
- If fuel switching is not possible or appropriate,
using more efficient equipment or tuning the existing
system can still improve energy efficiency.
- Will the planned renovation affect the mechanical
- Consult a professional heating contractor or
consultant. If you are doing extensive remodeling, it
is usually an opportunity to address any shortcomings
that may exist in your present system. Elements of the
mechanical system may also be more accessible during
- If air sealing, window replacement and insulation
upgrades are part of the work, combustion appliances
in the house may need make-up air to minimize pressure
- Central vacuums exhausting to the outside, as well
as dryers and range hoods, depressurize the house and
must be considered in the overall pressure balance of
- Is there a constant shortage of hot water?
- Have the hot water system checked by a
professional plumbing contractor. Hot water shortages
may occur from a change in lifestyle, number of
persons in the house, low temperature setting or
problems with the heating elements.
- Upgrade the hot water system to meet increased
needs. Insulate any hot water pipes that run through
an uninsulated or poorly insulated part of the house.
- Relocate the water heater if it is a long distance
from most of the bathrooms and kitchen.
- If temperature settings are too low, conditions
are appropriate for bacterial growth that could
- Lack of adequate hot water is unpleasant.
- Is it time to consider an air conditioner?
- Upgrade insulation, air sealing and exterior
shading devices to reduce overheating. Renovations are
a great opportunity to install these effective passive
- Consider upgrading or installing an air
conditioning system, especially as part of another
- High temperatures and humidity are not only
uncomfortable, but also unhealthy.
- A comfortable, warm interior environment will be
pleasant for your family.
- An even indoor climate is the result of a properly
functioning, energy efficient mechanical system that
is well matched to the design of the house. It will
offer superior indoor air quality and be easier on
Skills to Do the Job
A homeowner is usually able to assess the condition
install the replacement filters, following the
manufacturer’s instructions. However, the nature of
possible changes to the entire mechanical system may be
much more difficult. Because of the consequences of any
changes, most work must be done by qualified
tradespeople. Your local utility will be able to provide
advice or refer you to competent technicians who can
assess your home and the mechanical systems.
Heating contractors that install and service a
variety of heating system types should also be able to
give you advice. However, if they specialize in only one
type of system, they may not be able to provide
impartial advice on possible
Use the Mechanical Systems Assessment Worksheet to
record the present condition, any problems with your
mechanical system and preliminary costing.
Systems Assessment Worksheet|
|Type of Heating System
|Last Time Service Performed (There should be a
service technician's sticker on the unit.)
|Maintenance Service Costs
|Heating Cost And Amount Of Fuel Used (This would be
listed in energy units on fuel bills. Your utility can
often provide this information.)
Uneven heat distribution (cold spots in the
Effectiveness of thermostat
High fuel bills
Costing Your Project
Cost of mechanical system upgrades will depend on the work
that needs to be done. When reviewing bids from contractors,
make sure that the quotes you are comparing are for the same
work, including the same or truly equivalent equipment.
Other Useful Information From Canada Mortgage and Housing
Although this information product reflects
housing experts’ current knowledge, it is provided for general
information purposes only. Any reliance or action taken based
on the information, materials and techniques described are the
responsibility of the user. Readers are advised to consult
appropriate professional resources to determine what is safe
and suitable in their particular case. CMHC assumes no
responsibility for any consequence arising from use of the
information, materials and techniques