Quote: solar water heating and solar thermal
E.g.: 300L solar tank + roof collectors for a family of 4
Solar thermal supplies heat while photovoltaics produce electricity. Describe hot-water use, absences, existing tank and heater, roof and plant room. Specify hot water alone or additional space-heating support: the two scopes need different assessments.
Start with demand
Describe hot-water use and seasonality. Request useful heat, losses and backup estimates over the same period. Manufacturer diagrams separate collectors, transfer circuit and storage; enlarging only one component does not demonstrate improvement.
Check roof and pipe routes
Survey shade, orientation, slope, support, fixings and route to the tank. Specify waterproofing, insulation and service access. Compare flat-plate and evacuated-tube collectors with actual data and siting, not universal superiority.
Plan backup and periods without draw-off
Clarify solar priority, boiler, heat-pump or resistance backup, frost protection and operation when storage is hot but sun continues. Viessmann identifies oversizing and settings as assessment points. Brand-specific protection is not present in every system.
Check support conditions
The 2026 scheme specifies Solar Keymark, heat metering and building-age conditions for solar thermal, among other requirements. Check permit date, invoice and exact collector type. Hybrid heat-and-power panels must not automatically be assigned to this thermal grant category.
Organise commissioning and follow-up
Request tests, diagram, settings, heat-meter reading and model-specific service programme. Explain permitted user actions and alarm support. Shared buildings also need decisions, metering, cost allocation and an operator.
Indicative prices in Luxembourg
On quotation
Include collectors, mounts, storage, insulated pipes, controls, backup, protection and installation. Compare systems providing the same service. No average price, standard tank size or universal solar coverage is established.
Subsidies and grants
No grant is deducted from the budget shown here. If a quote mentions support, request the exact scheme and confirmation of your eligibility before including it in financing.
Frequently asked questions
Will solar provide all hot water?
Estimate coverage and backup for your profile. One percentage for all households is unjustified.
Are evacuated tubes always preferable?
Compare system performance on site, maintenance and cost, not collector type alone.
Can the old tank stay?
Only after checking compatibility, exchangers, capacity and control.
Do more collectors mean greater savings?
Not necessarily. Assess heat actually used and operation during periods without demand.