By Audrey HayesUpdated November 2026
Choosing a drainback solar hot water system comes down to a few practical questions: how many people you need to supply, whether your climate freezes, how much roof or yard space you have, and how comfortable you are with plumbing and pumps. This guide compares four drainback-style options from the product set we reviewed, using research-based criteria: manufacturer specifications, brand reputation, the consistency of owner feedback, and how well each design fits a typical residential setup. We have not tested these units ourselves, so treat the specs below as what manufacturers and listing details state, and confirm them against the product literature before ordering.
Our top picks at a glance
- 1
TOP CHOICEBest overallSolar Water Heating System Skyline5 Closed LoopView on Amazon - 2
Best for large households1000 Liter Water Heater Active Split System Dual Coil Tank 45 Deg FramView on Amazon - 3Best for smaller homes400 Liter Water Heater Active Split System Dual Coil Tank 45 Deg FrameView on Amazon
- 4
Best budget pick110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater SystemView on Amazon
Our Top Picks
Quick Comparison
| Product | Best for | Key feature |
|---|---|---|
| Solar Water Heating System Skyline5 Closed Loop | Homeowners wanting a complete, ready-to-plumb system | Closed-loop configuration |
| 1000 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified | Large households and high daily demand | 1000 L dual-coil storage tank |
| 400 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified | Smaller homes and apartments | 400 L dual-coil storage tank |
| 110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater System | Budget-conscious builders with a pump-based layout | Anti-dry-run float pump |
Solar Water Heating System Skyline5 Closed Loop
Solar Water Heating System Skyline5 Closed Loop
Best for: Homeowners who want a complete closed-loop system rather than assembling components separately.
This suits people who want the collectors, loop and storage matched by one manufacturer, which reduces the guesswork of pairing parts. It is a reasonable first choice for a standard single-family home in a climate without long freezing spells, since closed-loop designs use a heat-transfer fluid instead of potable water in the collectors.
Key specs
- Closed-loop configuration with heat-transfer fluid in the collector circuit
- Intended for residential domestic hot water use
Pros
- Matched components simplify system selection
- Closed loop protects the collectors from mineral scaling
- Suited to a conventional rooftop installation
Cons
- Glycol fluid needs periodic checking and eventual replacement
- Installation still requires solid plumbing and electrical know-how
Bottom line: A strong pick for homeowners who want an integrated closed-loop package and are comfortable with fluid maintenance.
1000 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified
1000 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified
Best for: Large households with high daily hot water demand.
A 1000-liter storage volume is sized for families or properties with several bathrooms running hot water across the day. The split active design separates the collector loop from the storage tank, which is the standard approach for larger systems. Plan for a substantial tank footprint and structural support.
Key specs
- 1000 liter storage tank
- Dual coil tank for auxiliary heat connection
- Evacuated vacuum tubes on a 45-degree frame
- Listing indicates SRCC certification
Pros
- Large storage buffers high-demand days
- Dual coil allows backup heating integration
- Evacuated tubes perform well in cool or cloudy conditions
Cons
- Large tank needs significant space and structural support
- Heavier installation effort for a DIY builder
Bottom line: Best for large households that have the space and the structure to support a big tank.
400 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified
400 Liter Water Heater Active Split System Dual Coil Tank 45 Deg Frame Evacuated Vacuum Tubes Hot SRCC Certified
Best for: Smaller homes, apartments and households of one to three people.
The 400-liter version uses the same split active architecture at a more manageable size. It is easier to fit in a utility room or on a modest roof section and is a better match for typical daily use in a smaller home. Because the design is the same as the larger tank, you get the same general approach to piping and controls at a lower scale.
Key specs
- 400 liter storage tank
- Dual coil tank for auxiliary heat connection
- Evacuated vacuum tubes on a 45-degree frame
- Listing indicates SRCC certification
Pros
- Compact storage fits smaller spaces
- Same split architecture as the larger model
- Dual coil supports backup heating
Cons
- Limited reserve on heavy-use days
- Still requires careful piping and freeze protection planning
Bottom line: The practical choice for smaller households that want evacuated-tube performance without a very large tank.
110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater System
110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater System …
Best for: Budget-conscious builders who want a pump-based system and are comfortable with a DIY layout.
This option centers on a 110-volt submersible pump with an anti-dry-run float, which protects the pump if the water level drops. It is aimed at people building a pump-driven loop themselves rather than buying a fully packaged collector and tank. Confirm the pump rating, head height and flow against your planned layout before buying.
Key specs
- 110-volt submersible pump
- Anti-dry-run float for pump protection
Pros
- Lower entry point for a pump-driven build
- Float switch helps protect the pump from running dry
- Flexible for custom layouts
Cons
- Requires you to source and match collectors and tank separately
- Needs a 110-volt power source and proper electrical protection
Bottom line: A sensible pick for experienced DIY builders who want a pump component and are willing to design the rest of the system.
Buying Guide
Drainback Operation and Freeze Protection
A drainback system works by draining the collector loop into a reservoir whenever the pump stops, so the collectors never hold water that can freeze. Check that any product you consider is designed for this operation and that the reservoir and piping are sized correctly. Plumbing that slopes consistently back to the reservoir is essential.
Good picks for this: Solar Water Heating System Skyline5 Closed Loop, 110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater System
Storage Tank Size
Match tank volume to daily hot water use. A common rule is to size storage to the household’s daily draw, then check that collector area can recharge it in a typical sunny day. Oversizing wastes heat through standby loss; undersizing leaves you without hot water on cloudy days.
Good picks for this: 400 Liter Water Heater Active Split System Dual Coil Tank, 1000 Liter Water Heater Active Split System Dual Coil Tank
Collector Type
Evacuated tube collectors tend to perform better in cool, cloudy or windy conditions than flat plates, because the vacuum reduces convective heat loss. Check the listing for the collector type and frame angle, and confirm the angle suits your latitude.
Good picks for this: 400 Liter Water Heater Active Split System Dual Coil Tank, 1000 Liter Water Heater Active Split System Dual Coil Tank
Certification and Standards
Look for independent certification such as SRCC (Solar Rating and Certification Corporation) on the listing. Certification indicates the performance data was verified under a recognized test standard, which makes comparison more reliable.
Good picks for this: 1000 Liter Water Heater Active Split System Dual Coil Tank, 400 Liter Water Heater Active Split System Dual Coil Tank
Pump and Controls
A pump-driven drainback loop depends on a controller, a sensor pair and a reliable pump. Check the pump voltage, head rating and whether a dry-run protection device is included. Pumps that run dry can fail quickly, so protection matters.
Good picks for this: 110v Submersible Water Pump Anti-Dry Run Float Solar Hot Water Heater System, Solar Water Heating System Skyline5 Closed Loop
Backup Heating Integration
Dual-coil tanks allow a conventional heater, such as a gas or electric unit, to supplement the solar heat on low-sun days. If backup is part of your plan, confirm the coil connections and controls are compatible with your existing water heater.
Good picks for this: 1000 Liter Water Heater Active Split System Dual Coil Tank, 400 Liter Water Heater Active Split System Dual Coil Tank
Installation Effort and Roof Loading
Large tanks and tube arrays add weight and wind load. Confirm roof structure and mounting with a licensed installer or structural professional, and follow local permit requirements. Consult a qualified professional before any roof penetration or electrical work.
Good picks for this: 400 Liter Water Heater Active Split System Dual Coil Tank, Solar Water Heating System Skyline5 Closed Loop
FAQ
What is a drainback solar hot water system?
It is a solar thermal system in which the collector loop drains into a reservoir when the pump stops. Because the collectors are empty between cycles, they are protected from freezing, which makes the design common in cold climates.
How is drainback different from a closed loop system?
Drainback systems use water in the collector loop and drain it back to storage when idle. Closed loop systems use a heat-transfer fluid, often a glycol mixture, that stays in the collector circuit year-round and exchanges heat through a heat exchanger.
Do drainback systems need a pump?
Yes. A pump circulates the fluid through the collectors while the sun provides enough heat, then the loop drains. A controller usually starts and stops the pump based on temperature sensors.
What size storage tank do I need?
Start from your household’s daily hot water use, then select a tank that covers that volume and can be reheated by your collector area on a typical sunny day. A qualified installer or the manufacturer’s sizing guide can confirm the right figure for your home.
Are evacuated tubes better than flat plates?
Evacuated tubes generally lose less heat to the surrounding air, so they often perform better in cool or overcast conditions. Flat plates can be more economical in mild, sunny climates. Compare the collector data for your location.
Can I add a gas or electric backup?
Dual-coil tanks are designed for this. A backup heater can top up the water when solar output is low. Confirm the connections and controls are compatible, and have a licensed plumber or electrician handle gas or electrical hookups.
Is a drainback system suitable for DIY installation?
Some builders complete parts of the work themselves, but roof mounting, pressurized plumbing, electrical wiring and structural loads carry real risk. Consult a licensed professional for those steps and check local permitting rules before starting.
Conclusion
For most homeowners, the Solar Water Heating System Skyline5 Closed Loop offers the simplest path to a matched, complete package, though it uses a closed-loop rather than drainback fluid approach. If you want a true drainback layout with evacuated tubes, the 400-liter tank suits smaller households, while the 1000-liter tank fits large families with the space and structure to support it. The 110-volt submersible pump option makes sense for experienced builders who want to design the rest of the loop. Match your pick to household size, climate and your comfort with plumbing and electrical work, and confirm specifications with the manufacturer before purchase.
Sources
- Federal guidance on solar water heating types, sizing and operation (energy.gov)
- Research on solar thermal system performance and design in residential settings (nrel.gov)
- Certification standards and performance data for solar collectors
Related reading
- What Is the Cheapest Solar Hot Water System? Options and Trade-Offs
- Sunbird Solar Hot Water System Prices: What You'll Pay and Why It Varies
- Split Solar Hot Water System Price: What You'll Pay and What Drives It
About Audrey Hayes
Audrey Hayes is part of our editorial team and reviews and edits our solar water heaters guides, checking product details against manufacturer specifications and owner feedback.
