Energy Consumption Explained – How Many Kilowatts?

As the cost of electricity continues to increase, customers are increasingly raising concerns about the spiralling costs associated with residential energy charges and how to combat the problem. You are not alone when you open your latest energy usage and think how did we use that much power in the last three months?

So you decide this time I am going to do some research online to see how you can address the situation and find there is plenty of information, some helpful and a lot not so much but as an electrical contractor, we are here to provide you with the correct information that will allow you to make informed decisions on energy consumption issues.

If you have a question or would like to discuss options in more detail then you can reach out to us through this link on the Contact Us page.

One of the first things to consider is the breakdown of how your electricity is being consumed, and the connected devices including heating, air-conditioning, storage-type hot water service, lighting, pool pumps, and other significant electrical appliances.

This article concentrates on the actual power consumption calculations (kilowatts consumed) rather than diving into the lumen efficiency factors between different lamp technologies but it is worth noting the following briefly.

50-watt halogen lamps typically produce around 700 lumens in light output whilst a tri-colour

A 13-watt led downlight selected to a cool white colour output will produce 850 lumens.

If you made the assumption that the led downlight consumes far less power (in – watts) then you are absolutely correct, the led downlight is better from an environmental perspective and will ultimately save you money in the longer term with a comparably short payback time following an installation upgrade.

The next point to consider is how much each appliance/device is consuming in watts and the following is a typical example – let’s take a 2.4-kilowatt space heater (2400 watts) which draws a 10 amp load from the supply and will consume 2.4 kilowatts of power for each hour that it is in use. Therefore if you run that appliance (space heater) for 4 hours – that will translate to 9.6 kilowatts of energy consumption.

Another example is halogen downlights, they are expensive to run with typically either 35 or 50-watt halogen lamps per downlight fitting, and a large portion of the energy consumed is lost through heat dissipation rather than the actual light output.

Consider the following scenario, you may typically use 14 halogen downlights spread across your kitchen, dining, and living areas, and let’s say you have 35-watt lamps installed in each fitting and we will need to add a 5 watts allowance to run the low voltage electronic driver (transformer). Therefore, we are typically consuming 40 watts per downlight fitting – this equates to 560 watts per hour in energy consumption.

Now take the second scenario where you have elected to change those downlights to a tri-colour 10-watt led downlight and allow the same 5 watts required to run the electronic driver (transformer) and you are now consuming 15 watts fitting – 210 watts per hour in energy usage.

Let’s do the maths side of the equation and compare the energy usage charges for a week’s duration being operated for 4 hours typically each night – 15,680 watts for the 35-watt halogen lamps versus 5,880 for the 10 watts led lamps delivering an energy saving of 9.8 kilowatts (9,800 watts) in total for the usage period.

The point to remember here is that each energy-saving device (downlights included) contributes over time and the hours in use towards the overall power savings achieved.

It may not seem a lot at first glance but when you start adding up all the downlights and then reviewing the energy savings it becomes plainly evident the efficiencies that can be achieved by switching to the modern generation-led technology.

The next area to research is websites that compare energy retailer plans and there are many to choose from online it is worth noting to investigate the retailer’s applicable discount structures on offer concurrently together with the contractual periods applicable.

Energy Tiers (Tariffs) Explained

Some energy retailer plans can be difficult to understand but they are commonly broken down into what is called tiers (tariffs) where you are charged in blocks for associated energy consumption.

They may be a flat line usage charge or a block type tariff where you pay a set amount for that tier (specified number of kilowatts) and the next block is charged at a higher tariff.

In effect, you are paying more for the next tier (block) though you have to look carefully at the fine print in the contract but be aware the majority of energy retailers charge daily service availability charges in addition to actual energy usage.

The other main type of retail energy plan is called Time of Use (TOU) where you may have various tariffs applied to different times of the day.

The plans are generally broken into three (3 x tiers) Peak – normally between 2.00 PM to 9-00 PM on weekdays, Off-Peak – normally 10.00 PM to 6.00 AM seven days a week, and Shoulder Periods which fit in-between these time parameters.

There are variations between retail energy providers regarding the TOU plans and quarterly variations therefore make sure you check the actual times with your retail energy provider.

The idea behind TOU tiers is to encourage energy usage when demand from the electricity grid is lowest (later in the evening) therefore you can actually save by setting the kitchen dishwasher, laundry washing machine, and storage-type hot water service to heat during these Off-Peak periods with time controllers.

The TOU tiers won’t work for everyone particularly those with young families and you have to be mindful that any usage during the Peak periods is going to attract charges typically at double the normal supply rate tariffs.

Therefore, you may be asking why to bother with TOU tiers. To answer this – if you are regimented and prepared to re-think your energy timing and properly manage the usage then you can save money over and above that as opposed to standard block form tariffs.

Only you can decide whether TOU tiers will save you money but as already mentioned – be aware the Peak period usage will typically cost double that of the normal supply tariff therefore consider carefully before proceeding with this type of tier.

A side note that you may find mentioned on some retail energy providers’ websites relates to what is called “Controlled Loads” (CLs).

Simply CLs usually relate to Off-Peak Hot Water Storage Systems (HWS) and don’t have any direct relationship to TOU tiers but are Off-Peak tiers that are remotely controlled by the applicable supply authority.

Once again there were variations to these tiers including Off Peak-1 and Off Peak-2 (longer heating time parameters) and Half Price Continuous variations but generally, they are now called controlled loads tied to Off Peak-1 where the HWS can reheat between typically 11.00 PM and 6.00 AM daily.

In conclusion, there are other power-saving options available that we haven’t discussed at this stage including the most popular option of solar array cells. Whilst a solar array system will offset your daily energy consumption depending on the size of the installation during the day – the net unused output from the solar system exported back into the grid now pays very small dividends and with the high costs currently for a battery storage system, careful consideration needs to be made to evaluate the payback period/asset re-payment timing considered the associated cost outlay before proceeding down this path.

If you are considering a solar array system and have weighed up the options then a few points to consider include allowing for an oversized inverter system that is capable of adding additional solar array cells at a later date.

The inverter system converts the generated solar electricity ready to be used within the residential installation with the net unused portion exported back to the grid supply.

Additionally, in order to keep the inverter system operating at its intended peak performance, a maintenance schedule needs to be considered because the solar array cells will need to be cleaned periodically otherwise there will be a reduction in solar conversion efficiency.

Critically it is quite important that any inverter system selected can be capable of being interlocked into a battery backup system at a later time frame when the cost of the storage batteries reduces over the coming years.

We have already seen market forces at work over the last few years with regards to led lighting where supply and customer demand tied to manufacturing competition has driven down the costs of led technology and when the popularity of battery backup systems gains strength it is anticipated that they will become a cost-effective option for residential applications.

Whilst considering points raised in this article you can take much smaller steps (cost-effective) by replacing some of the halogen downlights that will immediately begin to impact your energy usage – it’s more about looking for ways to reduce your total energy usage charges over each quarter that’s most important.

If you would like more information, would like to comment on the article or we can be of further assistance then Contact Us.