# Bathroom infloor heating

## Install and Running Cost Advice

If you have thought of having underfloor (under tile) heating installed to a bathroom, this information might assist you to estimate the costs.

## Bathroom Description

#### An example ensuite bathroom

Small ensuite bathroom of 3.5m x 1.6m (4.2sqm approx.)

Consists of a shower, WC and wall mounted double vanity basin.

## Install Cost

#### Based on a quote from P.A.P's Sydney Supplier based in Brookvale.

Install (Labour) - $160

Cable (Supply) - $290

Thermostat - $190

Break Alarm - $20

Total Supply and Install Cost = $660 + 10% GST = $726

## Running Cost Estimate

#### Master Ensuite (4.2sqm)

Approximate running costs are harder to work out, as it requires making estimates or assumptions about a few factors.

#### Θ Assumption #1:

Assumed usage set by thermostat / timer

= 5am - 9am morning and 5pm - 9pm evening

This is a total of 8 hrs / day, assume on only 6 months per year

#### Θ Assumption #2:

Duty Cycle = approx. 60%

(The duty cycle is an estimate of the proportion of time a system is drawing current opposed to being idle. On the advice we have received a room takes about 30-45 minutes to reach a desired temperature of say 22 degrees for a Bathroom). Heating up is when it is on, to maintain the temperature it is on about 60% of the time depending upon insulation of room / heat loss etc..)

#### Θ Assumption #3:

Assumed electricity Cost = 24c per kWh

(This varies a lot with different power providers and Flat rate vs Peak / Shoulder / Off Peak)

#### Θ Assumption #4:

Assumed power usage = 820W for 4.21 sqm ensuite

(This is from the quote so it is an easy assumption and means that for this size room you have 40.5 lineal metres of heating cable at 20 watts / lineal metre = 820 watts used when turned on.)

#### Running Cost Estimate - Master Ensuite (4.2sqm)

8 hrs x 365 / 2 x 60/100 x 0.24 cents x 0.82 kW

Total Running Cost: = $172 / per year

This formula could be used and modified for larger bathrooms.