What is the best way of heating a pool and spa?

The average pool/spa combo designed so that they can both be run through one set of pool equipment. There are a variety of ways of setting this up for heating a pool and spa.

You can use one set of pool equipment to run both the pool and spa. Valving is used to distribute the water and isolate the pool or the spa as required (depending on usage). Commercial pools and spas use designated equipment to run either the pool or spa. This means there is twice the amount of equipment required – a considerable added expense. Also, commercial spas have onerous water testing and sanitation requirements because they are permanently heated. Domestic pools do not have to be “heated on demand” like this. Public spas are permanently heated to 36°C and therefore require the water to be tested every 3 hrs. The heat causes them to become literal petri dish of organic compounds (and not the ‘good’ organic compounds)!

People often buy portable acrylic spas for their backyards which can be permanently heated by a low capacity electric resistance type heater. Such a method is reasonably effective because the polymer construction material the shell is built from, the thick foam filled covers, the air gap surrounding the outer spa shell and the deceptively small water volume make them energetically quite efficient. As to the sanitising of the water, these types of spas run high levels of sanitisers/oxidising agents/halides, etc. Often the suppliers “cheekily” market “bromine” sanitisers as a “chlorine free system.” This is deceptive marketing as Bromine is familial in its makeup and functionality with chlorine based systems.

Understanding Ambient Water Temperature

Ambient water temperatures in Melbourne are little known and as a result poorly understood. During peak summer, standing pool water – unheated – would be in the realms of 18°-20°C. Over winter the temp would be 10°-12°C. The temperature of the bay would be similar – but not as cold during winter as the ocean is a heat sink. The water temperatures indicated are surface temperatures only with the full pool depth temperature being around 3°C cooler.

If you think the standing temp of water at bay temperatures isn’t too bad – as you will swim in the bay over summer without too much discomfort, remember people swim in the bay mostly on those 30°C plus days when cooling off is a great option. Domestic pool usage is about cooling off but also about relaxing – and “chilled water temps” aren’t that relaxing. As a further descriptor people idealise ocean holidays on the Sunshine Coast – water temp 26°C in summer; Port Douglas 29°C. Nobody goes to Hobart for a seaside holiday at 18°C in summer.

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How Much Space Do You Need For a Swimming Pool?

A well designed swimming pool is a complimentary addition to any outdoor living area. Whilst visually the pool is often the focus – the purpose of your pool design should be the seamless use of the whole outdoor space year round. By this I mean ensure you allocate space and position the pool according to how you will utilise the remaining outdoor space.

For instance:

Grassed areas if you have kids and animals for play areas and free roaming year round
Al fresco entertaining and outdoor rooms will protect you from the sun in summer and keep you warm during the winter
Paved areas form platforms for outdoor furniture and thoroughfares for foot traffic
Planting and garden beds soften finishes and offer privacy
Pools serve a practical purpose for the Summer period (effectively from October to April if you have solar heating); and otherwise offer a purely visual function year round.

Even though I build swimming pools, I don’t think they are the be all and end all of outdoor design.

Here is an example of what we’re talking about – the pool is not too large to take up the garden, leaving plenty of space for other activities.

I think the design of pools and pool surroundings should be undertaken with a strong emphasis on the practical use of space. As a general rule the pool and pool surround should occupy an area of approx. 25% of the total available area. So if you have a small or medium sized backyard (~150 sqm), consider building a small pool from 20 – 28 sqm in size with a suitable small pool surround area. This allows plenty of room for you to use the outdoor area for the many other functions and if you can’t think of anything, imagine what kids – and those that think like them – would do with the space:

Kick the footy
Backyard cricket
Build a vegie patch etc.
Thrust up a clothes line
Build a shed and park a trailer

Your backyard is so much more than a swimming pool – it’s an outdoor entertaining area in which the design should be dictated by how you will use the space.

Key points:

Build your pool and pool surround to occupy approximately 25% of the total available area (especially if you have kids)
Ensure the pool surrounds occupy an area of approximately 50% of the pool surface area
A pool always looks good – so make sure you design it well so it looks great
Kids use pools -> Kids use backyards -> Adults pay for pools -> Pools pay for themselves when they compliment a property

How much access is required to build a swimming pool?

Modern building codes mean that many homes are now built on property boundaries with either no setbacks or limited setbacks. This means that full length car width access down one or both sides of a property are a thing of the past. Often when building a pool we will have as little as 800mm or doorway width to access a backyard and thus build a pool through.

Access widths are critical for the pool excavation with the efficiency / and therefore the cost of works being inversely proportional to the size of the equipment used. The larger the equipment used for the excavation works the lower the overall cost of the excavation. We can easily undertake all other aspects of a pools construction through standard doorway access.

We have our own tight access pool excavation equipment which allows us to efficiently remove all excavated materials from site. So as long as you have a doorway-sized opening to access the proposed construction area – we can build your pool.

Key points:

You can build a pool with almost any level of access
Minimum access requirements are a working width or opening the size of a standard doorway
The larger the excavation equipment you use the more efficient the process
A standard pool excavation with good access requires a 3 tonne bobcat , 4.0 tonne excavator and tandem truck. The average pool builder would allow $5,000 for excavating an 8.0 x 4.0m pool with the equipment listed above. To excavate a pool with ‘doorway’ sized access utilisng tight access equipment – a pool builder would allow approximately $8,000.

What are the costs of pool upkeep?

Consumables

We sell all our swimming pools with auto testing and dosing salt chlorinators. These units use salt dissolved in the pool water and convert it to Chloride ions which act as the sanitising/oxidising agent to kill organic matter within the water column. The average size swimming pool would use approximately 200kg of salt a year. This can be bought in 20kg bags of salt from Bunnings and pool shops from approximately $8 per bag. This means that the total cost for salt usage / sanitising the pool is around $80 per year.

The pool chlorinators also test and dose to manage the pH of the pool – they do this through dosing pool acid. A 15 LT drum of pool acid can be bought from Clarke Rubber for $22 a drum. The average pool will go through 3 – 5 drums of acid / year. This totals a figure of approx. $100 / year. At the start of and completion of each swimming season (October to April) additional pool water testing for Stabiliser concentration, total alkalinity and calcium hardness is required. Pool shops test water for free and will happily sell you the chemicals you need. A yearly budget of approx. $200 for these items is ample.

This means the average pool will cost approx. $400 for chemicals / year

A photo of a pool in hampton.

Electricity

Swimming pools are energy intensive to maintain primarily they use electrical energy to move water through the filtration and heating systems etc. But in addition they use gas to heat the water and even the sun to heat the water in solar pool heating systems.

Item	Electricity Cost per Year*
Pool Filtration Pump	$305
Solar Heating Pump	$317
Salt Chlorinators	$105
Infloor Cleaning	$1,058

*Based on 2015 electricity prices of $0.29 per KWhr

Upkeep on Plant and Equipment

There are some commercial realities that need to be considered in first answering this. Nearly every commercial product manufactured is not built prioritising durability; but rather commercial advantage. Pool equipment manufacturers are no different. Their business models are built around innovation and functionality with durability and longevity being supplanted by the knowledge that continuous re-imagining of function will make even the most durable product – out of date: Just think of mobile phones, the market drivers are functionality; whilst the concept of longevity needs to just meet the expiration date of your mobile phone contract.

So an honest reflection of the likely durability of significant pieces of pool machinery is as per the following:

Item	Warranty	Lifetime	Common Issues
Pool Pumps	3 years	5 – 10 years	Likely service issues include bearings and seals. Approx $200 to fix per item.
Salt Chlorinators	Up to 5 years	5 – 10 years	Likely to require salt cell replacement after 6 yrs. Cost $500
Gas Heater	1 – 2 years	6 – 10 years	Likely to require replacement of PCB board and screen – up to $500. Replacement of heat exchangers and burners $2-3K – may be required after 6 years or more years of use.
Sand filters	Up to 10 years		Sand requires replacement after 5 yrs cost $400; multiport valve may require replacement or servicing of seals after 5 or more years cost upto $500
Infloor cleaning	1 year		Infloor heads and water valves 5 – 10 yrs cost to change up to $5K

Checklist – Before you sign

The contract price must include and/or clearly state the following:

Access for all necessary building works and machinery must form part of the contract price and therefore not to be deemed as an extra at a later time.
A datum or fixed reference point must be nominated and the height of the pool to that datum point must be clearly shown.
The cost of all “Prime Cost” items and site cost must be clearly shown on the contract before you sign. “Price on application” is not acceptable for items such as tip fees. A breakdown of hourly rates and hourly equipment hire must be stipulated for items such as rock excavation and special equipment, etc.
If the walkway and coping is included in the contract price, the width must be nominated.
The costs of plans and specifications, and local government application fees (except for deposits and other charges). Council application fees can vary from council to council. If a council application is not included in the contract price, it must be stated as an additional charge if required.
All applicable State and Federal taxes on the Building Permit.
To prevent lengthy delays in obtaining approval from council, insist that your sales consultant submits plans to council within a reasonable time.
The maximum deposit you are required to pay on signing a contract for less than $20,000 is 10 percent and over $20,000 is 5 percent. This does not include statutory government charges and fees, insurance, etc.
Make sure the penalty costs (liquidated damages) for late completion are realistic…so your pool gets finished on time. (At least $50 / working day).
A cooling off period of 5 business days must be included in contracts exceeding $20,000.
Information regarding statutory warranty must be included in the contract.

Excavation:

The cost of overburden excavation and all above-ground formwork and structural requirements necessary to construct the pool in the nominated position, taking into account the height of the pool relative to its surroundings.
If cost of tipping is quoted, it must be included in the contract price.

Equipment:

The pool location on the property and the position of the filtration equipment must be clearly shown on a diagram. The contract price must allow for the supply and installation in these positions and for the supply and installation of all necessary pipework.
Sanitisation. What will it cost to keep your pool suitable for swimming and healthy for your family? Your consultant should be able to provide the answer. If in doubt, consult the manufacturer.
Solar Heating. Are you getting enough “collector” to adequately heat your pool? A rule of thumb is that a collector area of 80-100% of the surface area of the pool is required. Insist that the amount of collector is mentioned in the contract. If in doubt, consult the manufacturer.
The type of equipment appropriate for the excavation, including transporting to site, taking into account the access and working space.
Suitable filtration, sanitation and heating equipment to do the job. Make sure you check the suitability of the equipment before you sign. Otherwise, you may find you are charged more later for a “bigger size” or you haven’t got suitable performance out of the equipment provided. Check manufacturers’ recommendations.
Full details of the size of filtration to be supplied, including any accessories (light, heater, chlorinator, etc) should be provided.

Checklist – Pool companies

Use this checklist when you are deciding which pool companies to get quotes from:

Make sure the pool company you’re dealing with is not a fly-by-night operation. Be sure to check if they have extensive pool build histories. For instance request a detailed referral list and some jobs you can view.
If you get several quotes (3 is a good number), make sure they are based on the same specifications like equipment and building materials. Compile a spreadsheet and see who represents the best value for money.
Make sure the quality, brand, grade, weight, colour and size of materials to be used are stated in the contract. You’ll want some uniformity in the price quotes you get from the contractors.
Make sure that you’re dealing with only one contact person. Having to deal with several people will hinder communication and may even delay the completion of your swimming pool.
Walk away if the sales person puts any pressure on you to purchase the pool without extensive consideration of the deal and package on offer. If they quote the pool on the spot, ask yourself … how much consideration have they put into your pool project?
A contract should also include an appropriate date to start installation or construction; a completion date with appropriate understandings regarding delays; written understandings as to the consumer’s responsibility regarding additional costs such as hitting solid rock or water, the moving of utility lines, etc.; the size, shape and equipment; total costs, including scheduled payments with the last payment, often the biggest, determined by completion of the pool and your satisfaction.
There should also be well defined agreements for post-completion pool care. This includes guarantees and warranties.
Be sure to get all of the receipts for any money paid to the builder or contractor. If full payment is made in cash only, or a combination of cash or credit, be sure to obtain written verification of payment from the contractor with a list of the labour and material charges covered by that payment. Verbal agreements may not hold up in court if there is any discrepancy.
Make sure that the guarantee or warranty is fully disclosed. Find out if the entire job is under warranty or only certain materials and is labour included in this guarantee? Who will honour the guarantee — the dealer or the manufacturer? Remember a guarantee is only as good as the firm offering it. There may be problems if different parts have different warranties with different companies.
Does the company provide liability and worker’s compensation insurance to protect you in the event of an accident on the job? Installing pools can be very strenuous work, so always insist on a statement of coverage from the contractor’s insurance agent.
See that all work conforms to local building codes and regulations. If a permit is required, be sure that you comply with all specifications. Ensure that all construction conforms to building and contract requirements. You can get much of this information by going to the Victorian Building Commission.

You can never be too careful, even when getting a pool built. Try to follow this checklist as closely as possible to save your wallet and cover your back.

What about spas?

As a general rule we design all of our spas with one or all of the following design features:

Designated Jet pumps and plumbing
Blower grids in floor of spa operated by 6 amp blower. (Please note we fit 8 x 25 mm outlets in spa floor, not one or two.)
Large capacity 420MJ gas heater
Full width spillways – where possible (See an example image here)
Fully tiling
Tri-link control systems

A fully tiled spa. Note the 2 sided spillway and spa seat approx 500mm below water level.

We design most of our spas to be 4m² in size, approximately 2m x 2m in internal water dimensions. Spa water depth is usually set at 900mm. Seat width is usually 500mm with a water depth over the seat of approximately 500mm as well. In a 4m² spa we usually fit a 3 sided seat to the dimensions as above. We always fully tile spas.

Spa Equipment

Designated Jet pumps and plumbing – A 2.0hp jet pump with high flow plumbing lines can run up to 6 jets in a spa effectively. Filtration systems can’t run jets in spas at the level of effectiveness customers expect from their spa jets.

Blower grids in floor of spa operated by 6 Amp blower ( pls note we fit 8 x 25mm outlets in spa floor not one or two like some builders. Fitting only one or two often creates a volcanoe like effect.

Large capacity 350-420MJ gas heater – Large capacity spa heaters allow quick turn around times for heating spas in the middle of winter (usually 20 minutes to heat to 38ºC). We generally use a heater that has stainless steel burners for added durability and robust construction.

Pool/Spa control systems – We can install a functional control system that you can control from your Smart Device. It combines both pool and spa equipment, allowing you to control it through a single device.

What is a salt chlorinator?

A salt chlorinator generate chlorine through converting salt in solution in your pool water into the oxidising agent chlorine. Chlorine in turn acts to kill any organic matter in the water – such as algae, bacteria etc. Historically, chlorine has been used as an oxidising agent to sanitising pools. Even today, it is still added to drinking water to kill water borne pathogens. Salt chlorinators afford a simple, cost effective proven method of dispensing and sanitizing pool water without handling some of the noxious and deleterious chlorine based compounds.

You can read more about which sanitation systems we recommend here.

Robotic Pool Cleaners. Yes or No?

A resounding yes. Robotic pool cleaners are used in nearly every commercial pool in Australia. As such, the technology is proven, durable and highly effective.

These fully automatic robots remove the debris from the bottom of your pool silently each week when you drop them in the water. They cost approx. $2,000 (for a quality product), and use only a few dollars worth of electricity for the year. They are great value for money and the technology is getting ever cheaper. This is in contrast with in-floor cleaning which seems to defy the trend for manufactured items to be cheaper to buy now than in the past.

One of our most used robotic pool cleaners is the V4 4WD robotic pool cleaner by Zodiac.

Some of it’s notable features include:

Waterproof Kinetic Remote – Take control of the device with the waterproof remote to tell it exactly where to go.
eBox – The electronic control box makes it easy to control the V4 with the touch of a button which is programmable up to 7 days.
4 Wheel Drive – With it’s 4 wheel automotive drive system, the cleaner can overcome an array of obstacles with agility to assure every part of your pool is clean.
Compact – The V4 packs all these features into a small, efficient product which is easily stored away on it’s wheeled stand.

Take a look at the brochure for more information about the product.

In-floor cleaning. Yes or no?

We don’t view in-floor cleaning as a necessity. It works well, but is really expensive as an up-front cost (anywhere from $9- 15K). In addition it’s really expensive to run in terms of the electrical energy. It uses approximately $1000 of electricity per year (see calculation below) – which is a lot of money seeing all it does is remove the debris on the floor of the pool. We recommend robotic pool cleaners instead. Nevertheless we are only too happy to install in-floor cleaning systems.

Example of an in-floor cleaner.

In-floor cleaning manufacturers have been a little duplicitous in how they have packaged and marketed their swimming pool in-floor cleaning products. The notion that a pool with in-floor cleaning is “self cleaning” is a little mischievous in my book. There are 4 critical components involved in keeping a pool clean, of which in-floor cleaning is only one. These are:

Sanitation – removal of organic matter from within the water. Historically oxidising agents like chlorine have done this. Many people now use salt chlorinators for the same purpose

Filtration – the removal of inorganic ( sometimes organic matter ) suspended within the water column. The filter traps and stores fine particulate matter that would otherwise cloud the water when its in suspension in the water column

Skimming – the skimmer box removes floating debris from the surface of the pool. Often debris that is not skimmed off the surface falls to the bottom of the pool. Then and only then does infloor cleaning provide a meaningful benefit – as it acts to remove debris from the floor of the pool.

Debris removal from the floor of the pool – infloor cleaning systems remove debris from the floor of the pool, as do other forms of pool cleaners including robotic pool cleaners. Infloor cleaning systems use water jets in an energy intensive process to blow debris randomly around the pool and ultimately into a centralised pickup point for removal from the pool.

My argument on the value of in-floor cleaning isn’t that it doesn’t work. But rather it doesn’t represent value for money as its really expensive to sell for the re-seller ( the average pool builder like me) and hugely expensive for the end user ( pool owner) to purchase and ultimately to run ( – in terms of energy use).

In-floor manufacturers also point to other benefits like deep water circulation, heat retention and chemical savings etc. But I have never seen any independent studies commissioned to endorse these benefits – which is a certification you would want if your argument was sound. Instead I think these are illusory claims, which intuitively make sense – but quantitatively represent incremental gains at exponential costs.

This is a fact well evidenced amongst commercial clients who never specify infloor cleaning on any commercial or council facilities. In fact all council and local government facilities are cleaned by Robotic pool cleaners – and that’s what we recommend.

Infloor Cleaning Running Costs

The average price of electricity in Australia in 2015 is $0.29/KWhr.

The average infloor system uses a 2.5KWpump and runs for a period of 4 hrs per day.

The math is really simple. 365 (days) x 4 ( hrs / day) x (2.5(kW) x $0.29 (rate)) = $1058 – to run your in-floor pump; or more particularly to remove the debris from the bottom of the pool only.

Given, the average household electricity build is in the order of $500 / quarter. That infloor cleaning system will represent a 50% increase in your home electricity usage.