u/Biff0r

We’re at the point of replacing our gas boiler and are considering an air source heat pump. Since we already have solar, I’m trying to work out the best order to upgrade things without making an expensive mistake.

Current setup:

• UK, North Oxfordshire
• 18 solar panels, approx. 16 years old, south-facing roof
• Old FIT “rent-a-roof” scheme — currently trying to confirm who owns/controls it
• 3 kW inverter
• Annual electricity usage: around 3,040 kWh (Scottish Power)
• Solar generation last year: around 2,900 kWh

What I’m considering:

• Adding a battery system to reduce grid usage
• Installing an air source heat pump to replace the gas boiler
• Possibly upgrading the panels
• Possibly replacing the inverter
• Adding EV charging in future

What I want:

• Good Home Assistant integration for monitoring and automation
• Ideally a modular battery system that can be expanded later
• A setup that can support future EV charging and heat pump usage
• Advice on whether to phase the work or do more at once

Things I’m aware of:

• The FIT/rent-a-roof setup may restrict changes to the panels/inverter
• DNO approval may be needed if export capacity increases
• Heat pump demand will mostly be in winter, when solar output is lowest

Questions:

1. With this level of generation, does a battery make sense before upgrading the solar?
2. Should I leave the existing FIT/rent-a-roof system alone until ownership is confirmed?
3. Which battery/inverter systems work well with Home Assistant?
4. Any recommended installers or suppliers in/near North Oxfordshire?
5. Anything obvious I’m missing before I start getting quotes?
6. The heatpump will create more energy to be used almost double?