Warm air usually flows to a cooler place. During summer, it tends to flow from the outside hot environment into the house. On winter, it tends to flow from a warm in-house environment to the external colder environment. This process though easily prevented by insulation, comes at a cost.
Insulation, when done by yourself can be a simple home improvement process .i.e. batts insulation can be by nailing or stapling, foam panel insulation can be by simple cutting and fixing and reflective foil insulation can be installed by a staple gun. Although this is the case, it can sometimes turn messy and some insulation materials are not safe for handling. Therefore, it should be left to qualified, certified professionals.
According to statistics, an average home is about 2520 square feet with walls and ceiling for insulation. Depending on your budget, materials and other factors, the cost of insulation can vary as explained below;
- The Attic
According to experts, the cost of attic insulation ranges from $1.5 to $2.5 per square foot. (This can change by 100% if insulation is of blown type). Air sealing and Attic ventilation will have to be taken care of during this process at a cost of $45 to $55 per ventilating unit.
Homes built in early years were constructed with two wall layers leaving a cavity between them. Cavity wall insulation is the filling of this gap to reduce condensation from external wall, enhance warmth and save energy.
To consider cavity wall insulation, your home should;
- Have been built more than ten years ago and doesn’t have insulation. You can confirm this with the help of a registered installer. By drilling a small hole into your house wall (boroscope inspection), to confirm presence or absence of insulation material. Alternatively, confirm from the local authority building control department.
- Have a wall cavity of more than 50mm
- Not have walls exposed to driving rain and no leaks. If internal walls are found to be dump during the insulation process, registered damp prevention experts should be contacted to take care of the dampness problem first.
- Have good brickwork.
- Have easily accessible external walls. If they are joined to another house, a cavity barrier is inserted to protect from any effect.
The insulation material is then blown into the 50mm cavity from outside the house (through 22mm drilled holes) to fill every part of the wall. After filling, the drilled holes are professionally sealed, not to be noticed.
Cost of wall cavity insulation
The insulation material is mainly made from mineral wool, foamed insulants and beads all manufactured as per set standards and professionally certified. Before purchase, it is important to determine the thermal resistance or R-value that is to be achieved. The better the material is in insulation, the higher the thermal resistance (R-Value).
For wall cavity insulation, most professionals charge $2.50-$3.50 per square foot. This also varies from $ 1100-$3600 for a thousand square feet.
It is important to note that, some companies encourage insulation by offering insulation rebates and discounts. Therefore, before purchase and installation of any insulation material, ensure you are informed about the local insulation services offered.
The following are annual estimates of savings that can be made with wall cavity insulation on a gas heated home. (They are not definite)
Type of building
|Flat||Bungalow||Mid Terrace||Semi Detached||Detached|
|Saved carbon dioxide in a year||330kgs||430kgs||400kgs||700kgs||1140kgs|
Less than five year period
- Floor insulation
Floor insulation is the addition of insulation materials below floor boards to minimise loss of heat into the ground. Sometimes draughts come into the house through floorboards and insulation works to reduce this. According to research and statistics, 16% of heat loss is via the floor. Apart from new floor insulation, retrofitting can also be done.
Floor insulation can be done by yourself at home however it is advisable to involve a professional since some insulation materials e.g. glass wool are not safe when handled without protective clothing.
If rooms below are heated, it is not necessary to insulate floors on 2nd or 3rd floors.
Cost of Floor Insulation
A roll of floor insulation fibre 7 metres in length and 1m in width, costs £15. For concrete floors, insulation boards 2.4 metre length and 1.2 metre width Cost approximately £20. These come in different sizes and thickness therefore offering different levels of desired insulation.
Floor insulation can also be done using butt materials. As represented in the table below, the cost of batt floor insulation depends on material cost, labour time and cost of materials.
|Common Mid-Grade Batt Insulation Cost||For 200 square feet||$ 80.00||$90.00|
|Batt Insulation Labour||4.0 hours||$105.00||$200.00|
|Cost of Materials and Supplies e.g. fasteners, sealing tape among others||190 square feet||$20.00||$30.00|
|Installation Costs||190 square feet||$195.00||$305.00|
With the above information, average cost of batt insulation per square metre can easily be obtained.
- Warehouse insulation; Cost of materials
This depends on the size of the warehouse and the type of insulation material. The following is a rough estimate cost representation of quality materials for insulation.
Under-floor insulation materials; if the size is of 80 square metres, the estimated cost will be between $ 160 and $800. If it’s of 110 square metres, the cost will vary from $220 to $1100 and that of 130 square metres, the cost will be between $260 and $1300.
Ceiling insulation materials; for 80 square metres, the estimated cost will be between $400 and $1200. If it’s of 110 square metres, the cost will vary from $550 to $1550 and that of 130 square metres, the cost will be between $650 and $1850
Cost of warehouse insulation
The following is a rough estimate cost representation of quality insulation.
Under-floor insulation; for perfect insulation, charges vary from $18 to $20 per square metre. For fair or good insulation, one pays from $13 to $17 per square metre.
Ceiling insulation; charges vary from $10 to $20 per square metre depending on the grade. (Inclusive of materials and labour)
It is important to note that the costs and prices as explained above are not definite and can vary depending on place or locality. They should just act as a guideline.