What is an evacuated tube?

An evacuated tube consists of two rows of glass tubes that are sealed on the ends in order to form a double wall vacuum. Read more here…

Is solar water heating a viable alternative to gas or electricity?

Yes, it is only the size of your hot water storage tank that limits the amount of hot water that a solar system can supply. Complete off-grid systems can be designed to fulfill your electricity and water heating requirements all year round. Simple cost-effective grid-tied solutions typically use solar as a supplement to gas or electricity systems and are sized to provide 60%-70% of a household’s hot water needs. Read more here…

How long will it take to pay for my investment?

Lumos Solarizer DHW systems are the most cost effective solution available on the market today. Payback times depend on many variables, mainly whether your current hot water system is powered by natural gas, electricity, or propane. By way of example, a household that spends 25% of its electricity bill on hot water heating, the payback can be as soon as 4-5 years.

Can evacuated tube collectors be used in cold and mountainous conditions?

Yes, evacuated tube performance excels in cold and mountainous conditions. They produce more energy early and late in the day in comparison to flat plates. They have a tendency to shed cold mountain snow (see picture). When they do ice up they do retain ice a bit longer because they do not loose heat like a flat plate panel (so what they may not collect during icing, the flat plate probably looses in efficiency over the year).

What about hail damage?

Our evacuated tubes are made from borosilicate glass (trade name Pyrex), which is extremely strong and can withstand hailstones up to 1.5” (35mm).

What happens if a solar tube breaks?

If the worst happens, individual tubes can be easily replaced and the collector can continue to function with a broken tube, or tubes, with only a slight decrease in efficiency.

Do they work in cloudy conditions?

Evacuated tube solar collectors have a clear advantage over flat plate collectors in cloudy conditions.

Can I use a solar collector with my existing hot water system?

Yes, this is typically the most cost effective way to implement solar into your house. If your tank cannot accept the solar heated water directly then an additional “side arm” storage tank to preheat the cold water prior to entering the existing tank. Read more here…

Will I see the collectors on my roof?

The collectors need to be mounted on an un-shaded roof with a south facing aspect. Ground mounting is another option to place the collectors in an out of the way location on your property. Click here to view installation photos.

Can they be mounted on a flat roof?

Yes, they can be installed on a flat roof when mounted on a tilt-up rack to keep them at the best angle for solar absorption.

What is the ideal installation angle?

The ideal angle of tilt is approximately equal to the latitude, i.e., about 40 degrees in Colorado. The angle of tilt of a normal roof is acceptable and normal practice. The recommended tilt angle range is 15 degrees to 75 degrees. Because the winter sun is lower in the sky, a steeper angle favors winter performance over summer, hence is preferable. In practice, simplicity is more important than exact angles. 45 degrees off the ideal angle reduces performance by only about 10%. It is better to compensate for a less than optimal roof angle by a larger panel than by complicated panel positioning.

What about operating in subzero temperatures?

We recommend using closed loop glycol systems in extremely cold environments. Read more here. In temperate climates freeze control can be maintained by programming the controller to circulate heated water from the tank to the collector when the collector manifold temperature drops below a preset level. Drain-back systems are another option for freeze protection where the water in the collector loop is drained back to a holding tank in the mechanical room when the collectors are not producing heat (at night) and outside temperatures drop below freezing.

Can the system overheat?

Yes, Lumos evacuated tube solar collectors can easily bring water to the boiling point in good weather. It is very important to design your system size correctly and to make sure that all the BTU’s being produced by your system are being used on a daily basis, or that you have adequate storage space to “stockpile” heated water that is not used. Stagnation is a special consideration in closed loop glycol systems. If the system is not using the energy from the collector the glycol can boil away and leave behind a sticky residue which can damage a systems plumbing. Drain back systems are typically used to handle stagnation overheating situations. Alternatively, “heat dumps” can be used to get rid of excess energy, either wastefully through finned heat coils, or creatively by dumping the energy into another system such as space heating, geo-thermal, hot tubs, pools, etc.

Can the system be a fire hazard?

No, the Lumos evacuated tube solar collector components are all non-flammable. Even when the system is not circulating heat transfer fluid (whether glycol or water) and the tubes are producing heat (stagnation) the system is non-combustible.