Solar Pumping Solutions
solar hot water
Frequently asked questions - solar hot water
- How does a Hills Solar evacuated tube water heater work?
- How does gas boosting work? Does it turn on when I'm not using hot water?
- Are the Hills Solar evacuated tubes affected by frost?
- What happens to my hot water if the Hills Solar evacuated tubes are broken?
- How long does it take and cost to install my Hills Solar Hot Water System?
- Are Hills Solar Hot Water Systems expensive?
- What rebates exist for the system and how do they work?
- How can I be sure of the quality and performance of your products?
- How many RECs does the Hills Solar Hot Water System achieve?
- Who will install the Hills Solar Hot Water System on my roof?
- How many people will the Hills Solar Hot Water System service?
- Does a Hills Solar Hot Water System offer advantages for my investment property?
- How did you estimate the average saving value for my electric/gas hot water unit?
- What tariff should my electric boosted Hills Solar Hot Water System be connected to?
- Is solar water heating a viable alternative to gas or electricity?
- How long will it take to recoup my investment?
- Can Hills Solar Hot Water Systems operate effectively in cold conditions?
- Will my water be heated on a cloudy day?
- Can I use a Hills Solar collector with my existing hot water system?
- Are the collectors noticeable on the roof?
- Can the collector be mounted on a flat surface?
- Will the Hills Solar collector be a fire hazard during hot, dry weather?
- Can the Hills Solar collector heat water to a high enough temperature?
- What maintenance of the Hills Solar collector is required?
- Can Hills Solar Hot Water Systems be used for a large scale hot water production?
- Can I heat my swimming pool or spa using a Hills Solar Hot Water System?
- Can I use the LPG gas booster and then convert to normal gas if available at a later stage?
- Which type of collector is the best value for money?
- What are the main advantages of the Hills Solar evacuated tube collectors over flat plate collectors?
- Does the Hills Solar collector have to be installed on a north facing roof?
1. How does a Hills Solar Evacuated Tube water heater work?
Most solar water heaters use flat plate technology which has been around for many years. It works – but there is a longer lasting, more efficient, better looking alternative: Hills Solar Evacuated Tubes. 
Hills Solar Hot Water Systems use state-of-the-art technology based on evacuated glass tubes and highly efficient heat transfer techniques.
A key benefit of the evacuated tubes used in Hills Solar Hot Water Systems is that they are round. They therefore, always face the sun and can absorb more of the sun’s energy. In contrast, flat plate solar water heaters are only at their maximum efficiency in the middle of the day. A great deal of the sun’s energy is simply reflected off the flat glass panels, especially in the morning and afternoon.
In fact, a Hills Solar collector can absorb up to 40% more of the sun's energy when compared with a comparably sized flat plate solar collector.
The Hills Solar Evacuated Tubes consist of 2 layers of toughened glass (like Pyrex) with a vacuum between these 2 layers. This evacuated layer in the tubes acts much like a thermos flask, retaining around 97% of the energy absorbed from the sun. This helps increase the efficiency of the collector and also protects it from the effects of cold air (the water in flat plate collectors can freeze in very cold areas).
As a result, the Hills Solar evacuated tube solar collector is the perfect system for very cold areas being frost protected down to minus 40 degrees Celsius.
The sun's energy that is absorbed by the tubes is then transferred to your water via special heat pipes located inside each tube. A small amount of water is inside each heat pipe. This is turned to gas by the sun, this gas rises to the tips of the pipes, which are inserted into a heat transfer manifold located on your roof. Water is pumped through this manifold absorbing the heat and is then stored in a water storage tank located below.
The result is an incredibly efficient system specifically designed to harness the heat of the sun even in extremely cold areas. Because the system is so efficient it does not require full sun and can work on cloudy or even rainy days.
Stylish Split System Design
The system can be boosted, when required, by gas or electricity, or even the heat that would otherwise go to waste from a combustion heater. For a large part of the year you will find you will not need any boosting due to the superior performance of the system.
2. How does gas boosting work? Does it turn on when I'm not using hot water?
No. Our natural and LP gas systems turn on and boost only when they detect that the temperature of the water coming out of the tank has fallen below 60ºC. The gas booster only boosts the difference in temperature between the stored water and the 60ºC setting required on the gas booster. This may occur when you have used some or all of the solar heated water in your storage tank or during extended cloudy periods.
3. Are the Hills Solar evacuated tubes affected by frost?
The Hills Solar System has passed the AS / NZS 2007 Standards for Severe Freeze Conditions to -15d Celsius.
The Hills Solar Hot Water System does not have any water entering the tubes and uses heat pipe technology to provide a system that can be subjected to very low temperatures without freezing or the need for glycol. In cold climates it’s a clear winner. Scientists have recently installed several evacuated tube systems in Antarctica.
4. What happens to my hot water if the Hills Solar evacuated tubes are broken?
The Hills Solar System is very strong and uses toughened glass that is highly resistant to damage under various weather conditions. However, because the system is modular, if a single glass tube is broken then it can be easily replaced for a small fee. Meanwhile, the system can continue to operate without leaking and with only a small reduction in overall efficiency. Since the system is sealed and works with a booster, you can even continue to have hot water even if every tube was broken in a major storm.
Hills Evacuated Tubes have passed the AS/NZS 2712:2007 Standard testing for hail resistance.
5. How long does it take and cost to install my Hills Solar Hot Water System?
Installation is easy. Because Hills Solar Hot Water Systems are lightweight, modular and include comprehensive installation instructions, you can expect an average installation to take 6 to 8 hours, depending on whether you are retrofitting an existing home or new home and how experienced and knowledgeable the plumber is.
6. Are Hills Solar Hot Water Systems expensive?
No. In the long term, a Hills Solar Hot Water System can reduce an average household’s cost of heating water by as much as 80%, therefore reducing a household’s total electricity or gas expenses by up to 30% over a 10 year period. The total cost of a Hills Solar water heater is cheaper than buying a straight electric or gas hot water heater due to its much lower running costs. Also, the components that we use are designed to last. The steel that we use in our storage tanks is marine grade stainless steel with a polymer outer casing, making our systems particularly well suited to humid climates and coastal areas. It also gives them a much longer expected life than cheaper vitreous enamel tanks. In short, the superior quality of our components make the system better value for money.
7. What rebates exist for the system and how do they work?
Solar hot water rebates are available from the Federal Government. These are called Renewable Energy Certificates or RECs. Some states also offer additional rebates. The RECs program is aimed at increasing the installation and use of solar hot water systems by providing redeemable certificates that consumers receive after purchasing a solar hot water system. The amount and value of RECs received depends on the type of system purchased. It is important to note that RECS cannot simply be cashed in. Instead, they must be offered for sale in the RECs marketplace. The potential buyers are energy companies who have been required by the government to acquire a set level of RECs. The value of RECs has fallen considerably from the beginning of the scheme, as many energy companies have acquired a sufficient stock of RECs.
New $1000 Federal Government Rebate available for systems installed on, or after July 18 2007
Click here for more information
New NSW State Government solar hot water rebate
Click here for more information
8. How can I be sure of the quality and performance of your products?
The range of Hills Solar water heaters meet the rigorous tests set by the relevant Australian industry standards and are made from the high quality components backed by generous warranties. Our systems meet the requirements of the various state and Federal Government rebate programs and attract some of the highest energy performance ratings in the market. Hills Industries chose the Solar system above all others, based on its performance, ecological impact and longevity. The system has received much praise from customers and some of their testimonials are on this website (click here for testimonials).
9. How many RECs does the Hills Solar Hot Water System achieve?
This depends on what system you purchase. However, as a general guide you can expect to receive from around 24 to 45 RECs.
10. Who will install the Hills Solar Hot Water System to my roof?
The Hills Solar Hot Water System should be fitted by an authorized and registered plumber, who will ensure it is positioned correctly. We can recommend and arrange a trained Green Plumber in your area.
11. How many people will the Hills Solar Hot Water System service?
Solar Pumping Solutions will recommend the type and size of Hills Solar Hot Water System right for your house, based on a thorough questionnaire. The factors include: the number of people living in the house, the number of bedrooms, the number of bathrooms and spas, the geographic location and the unshaded roof areas available for mounting the collector. There are systems to suit every home.
12. Does a Hills Solar Hot Water System offer advantages for my investment property?
Yes. The Hills Solar Hot Water System offers some major advantages to property investors, such as reducing gas or electricity bills for tenants and showing that the property is contributing to the lowering of greenhouse gas emissions. Advantages include reducing your properties gas or electricity bills and increasing the value of your property. You can also add your Hills Solar Hot Water System to your depreciation schedule and claim it as a tax deduction.
13. How did you estimate the average saving value for my electric/gas hot water unit?
A credible source for this type of information are Sustainable Energy Development Office website ‘How to choose a hot water system’ at:www1.sedo.energy.wa.gov.au/pages/runsolhw.asp
14. What tariff should my electric boosted Hills Solar Hot Water System be connected to?
The Hills Solar Hot Water System should generally be connected to an Off Peak Tariff where possible. A qualified electrician can recommend the best alternative for you if you don’t have off-peak available. In such circumstances an electrical timer can be used to help ensure that your electric booster only runs during times of the lowest energy tariff. Please contact your energy provider to confirm your requirements, as each state varies.
15. Is solar water heating a viable alternative to gas or electricity?
Solar hot water should generally not be seen as a complete alternative to gas or electricity, but rather a major partner. Solar will not totally replace the need for gas or electric heating in most cases, as there are inevitably days when there is little sunlight. However, when averaged over a year, a correctly-sized solar system can provide up to 80% or more of a household's hot water needs. The hot water system can easily be automated so hot water is guaranteed regardless of sunlight levels. If clients request a complete alternative, in some cases an oversized system can provide 100% of their hot water needs.
16. How long will it take to recoup my investment?
Your annual electricity or gas saving will differ depending on the climate and sun angle in your location and current hot water usage. However, in a normal household that spends 40% of its energy on heating hot water, the full cost of the purchase may be recouped in as little as 5 to 7 years via reduced bills when compared with the cost of a standard electric hater heater. The quality and durability of the materials used in a Hills Solar Hot Water System mean that your yearly savings will likely continue long past the pay-back point.
17. Can Hills Solar Hot Water Systems operate effectively in cold conditions?
Yes - Hills Solar collectors can operate in conditions far below freezing, although performance can be reduced in such extreme conditions. The Hills Solar System has passed the AS/NZS 2712:2007 Standards for Severe Freeze Conditions to -15d Celsius. Good heat output is achieved in sub-zero conditions as long as there is sunlight. This represents the major performance difference between Hills Solar evacuated tubes and the old-fashioned flat plate solar collectors, which suffer from significant loss in efficiency in cold conditions, as well as requiring the purchase and maintenance of a glycol system to prevent them freezing.
18. Will my water be heated on a cloudy day?
Yes, although the heat output of the solar collector is reduced on overcast days it will still be able to provide heating. If it is a heavily clouded day or is raining, then gas or electric backup may be required to maintain water at the required temperature if a significant amount of hot water is drained from the tank. The operation of this boosting is automated, so you don't have to worry about running out of hot water during an extended rainy period.
19. Can I use a Hills Solar collector with my existing hot water system?
Yes, the Hills Solar collector can be retrofitted to most existing tanks using our special conversion kit. We do recommend that you consider replacing your existing tank if it is more than five years old, since normal vitreous tanks often have a limited life after this period. We can replace your old tank with a long-lasting, well-insulated marine grade stainless steel tank. In many cases, the RECs rebate can reduce the additional cost of a new tank to a marginal figure and customers often prefer to replace the entire system with the knowledge that they will have many years of trouble-free service ahead.
20. Are the collectors noticeable on the roof?
The sleek design of our collector, combined with the lack of tank on the roof mean that it is very unobtrusive. From a distance they actually look somewhat like a skylight. However, please check with your local council regarding any possible building restrictions in your area.
21. Can the collector be mounted on a flat surface?
Yes. Hills Solar collectors can be mounted on a flat roof or even on the ground by using one of our fully adjustable high quality stainless steel frames.
22. Will the Hills Solar collector be a fire hazard during hot, dry weather?
No. The solar collector's components are all high temperature rated and non-flammable, so even during strong sunlight with the circulation pump turned off (stagnation) the system will not catch alight or give off any sparks. The majority of the solar collector's components are stainless steel, aluminium, glass or glass wool. The insulation material used to insulate the outer piping close to the collector should be rated to at least 280ºC if the system is likely to stagnate during periods of strong sunlight.
23. Can the Hills Solar collector heat water to a high enough temperature?
Certainly - in good weather the Hills Solar collectors are capable of bringing water to boiling point. Generally, this is not necessary and so the system should be tuned to provide a peak temperature of around 70 to 80ºC in the summer. Since scalding can occur at 54ºC (130ºF), Australian plumbing regulations limit the maximum temperature of hot water to sanitary outlets to 50ºC (122º F). This is achieved by the use of a solar tempering valve that must be fitted to every installation.
24. What maintenance of the Hills Solar Hot Water System is required?
Under normal circumstances no maintenance of the system is required other than simple checks specified in the Owners Manual. The round shape of the tubes and the gaps in between them mean that regular rainfall and wind help keep the tubes clean.
25. Can Hills Solar Hot Water Systems be used for a large scale hot water production?
Yes. Hills Solar collectors can be connected in series to provide large scale hot water production for commercial settings such as a school, hotel, or office building.
26. Can I heat my swimming pool or spa using a Hills Solar Hot Water System?
At this stage, we do not supply a product for heating pools and spas, but this area is being investigated.
27. Can I use the LPG gas booster and then convert to normal gas if available at a later stage?
Yes. You will need to have the burner manifold changed and have the PC board reprogrammed. The cost is currently around $80.
28. Which type of collector is the best value for money?
Rather than looking at just peak efficiency levels when comparing solar collectors, cost per unit of energy produced is a much better guide. When pay-back time is being considered, price per unit of energy produced is the most important consideration, not peak efficiency levels. The efficiency and longevity of Hills Solar Hot Water Systems gives them a compelling case for purchase over other systems.
29. What are the main advantages of the Hills Solar evacuated tube collectors over flat plate collectors?
There are numerous differences between the two types of Solar Hot Water Systems available in Australia. Some major distinctions include:
INCREASED EFFICIENCY
Flat plate collectors provide peak energy output at during the middle of the day, when the sun is perpendicular to the collector's surface. Due to the cylindrical shape of the evacuated tube, the sun is perpendicular to the surface of the glass for most of the day, resulting in good heat output from morning through to late afternoon. The ability of the tubes to absorb heat from a wide range of angles means that they do not need to be mounted on north facing roofs only – they can be mounted on east or west facing roofs with only a small decrease in performance.
MINIMAL HEAT LOSS
Because air is evacuated from the glass tubes to form a vacuum, it greatly reduces conductive and convective heat loss from the interior of the tube. As a result, wind and cold temperatures have much less effect on the efficiency of the evacuated tube collector. The system conducts heat via a small amount of water being turned into superheated steam. Thus heat is conducted efficiently, while cold is not.
HIGH FROST PROTECTION
Hills Solar collectors can be used in sub-zero temperatures without the system sustaining damage. Hills Solar System has passed the AS/NZS 2712:2007 Standards for Severe Freeze Conditions to -15d Celsius. In similar conditions flat plate systems require expensive and complicated "antifreeze" systems to be installed (remember this when comparing system costs). The poisonous glycol that is used in flat plate systems needs to be regularly replaced in order to maintain its efficiency – an ongoing cost, with the added risk of the glycol leaking into gutters or rainwater tanks during the glycol changeover or if the flat plate is damaged by storms.
SUPERIOR WINTER PERFORMANCE
The high solar energy absorption of the Hills Solar evacuated tube collectors, even during overcast conditions, combined with the superior insulation properties of the tube, provides excellent water heating all year round. While some flat plate collectors may produce similar heat output in summer conditions, they generally have lesser performance during winter - when hot water is most needed.
30. Does the Hills Solar collector have to be installed on a North facing roof?
Because of the significantly better efficiency of a Hills Solar evacuated tube collector in harnessing the sun's energy, you can locate your system on a roof areas facing north-east or north-west with minimal reductions in efficiency (2% to 4% loss) or on a west or east facing roof (6% to 10% loss in efficiency). Even if the only unshaded place to mount the collector is on a south facing roof, a collector can be mounted on a reverse frame facing north. However, generally speaking the best place to locate your solar collector is on a north facing roof with a slope of 20 to 45 degrees.