Compare TOPCon and HJT models using available roof space, installed price, monthly generation and warranties.
Compare both quotations on your roof
Request the exact models, layout and installed price for each option. Keep the same scope for inverter, mounting, wiring, roof access and service. If total capacity differs, show that difference in the result: extra generation from more installed capacity does not establish a better cell technology.
Assess a roof with limited space
For a roof interrupted by a dormer or chimney, compare the capacity actually fitted and the retained access routes. Module efficiency can matter, but dimensions and layout also determine panel count. Request both options on the same dimensioned plan. Record unusable areas rather than simply multiplying advertised efficiency by the entire roof area.
Assess a project with a limited budget
Separate module prices from total project costs. For the more expensive option, calculate estimated additional kWh, the share used on site and the share sold. Use the same tariffs and consumption in both calculations. Include service, losses and planned replacements. A uniform price premium for all HJT panels or an automatic TOPCon ranking does not replace actual quotations.
Check the season that matters to you
If winter generation for heating is your priority, request monthly results. Use the same weather, shading, operating-temperature assumptions and inverter model for both options. Specify the low-irradiance data used and the result’s uncertainty. The HJT name does not guarantee a fixed gain on a north-facing roof; snow covering the panels should also be included in the assumptions.
Confirm the proposed purchase
Put model, quantity, delivery date and substitution terms in the quotation. Compare product and power warranties, claims conditions and covered costs. Ranges from the same brand may use different cells: LONGi describes Hi-MO X10 as back-contact HPBC 2.0. Check the exact datasheets and identify the Swiss service provider before choosing.
References for your comparison
Fraunhofer ISE — TOPCon passivated contacts · PVsyst — low irradiance · LONGi — Hi-MO X10