Frequently asked questions

In Estonia, 1 kW of solar capacity produces on average about 900–1000 kWh of electricity per year. Exact output depends on location, orientation, tilt angle, and shading. For example, a 10 kW system typically produces around 9000–10000 kWh annually.

For a private home, solar installation typically costs about €1000–€1500 per kilowatt. That means a 10 kW system usually falls in the €10,000–€15,000 range. The final price depends on panel quality, roof type, installation complexity, and any additional equipment.

In Estonia, a solar investment typically pays back in about 7–10 years. Payback depends on electricity prices, self-consumption rate, available subsidies, and system size. With batteries, payback can be slightly longer, but energy independence is higher.

Quality solar panels last 25–30 years or more. Manufacturers typically provide a 25-year performance warranty, guaranteeing at least 80% of original output after 25 years. Inverters have a shorter lifespan (about 10–15 years) but are replaceable.

Solar panels are practically maintenance-free. Rain usually keeps panels clean enough. We recommend checking the system 1–2 times per year and cleaning panels if needed using soft tools and water. It’s also worth monitoring inverter readings and production.

Yes, solar panels work in winter, but output is lower due to shorter days and a lower sun angle. In December–January, production is typically 5–10% of annual output. Snow usually slides off angled panels on its own. Cold temperatures can even improve panel efficiency.

A battery isn’t mandatory, but it significantly increases energy independence. Without a battery, you export surplus to the grid and buy electricity when you produce less. With a battery, you can store daytime production for evening and night use. Batteries typically pay back in about 8–12 years.

Battery size depends on your consumption and your self-sufficiency goals. A typical home uses a 5–15 kWh battery. A 10 kWh battery usually stores enough energy for an average family’s evening and night usage. Our specialists calculate the optimal capacity based on your consumption.

Today, the best option is lithium-ion (Li-ion) batteries, especially LFP (lithium iron phosphate). They’re safe, last 10–15 years (6000+ cycles), are efficient (90–95%), and compact. We use only top-quality manufacturers such as Tesla, BYD, Huawei, and SolarEdge.

Modern lithium-ion batteries last 10–15 years or around 6000–10,000 charge cycles. Manufacturers typically provide a 10-year warranty guaranteeing at least 70–80% of original capacity. Exact lifespan depends on usage intensity, depth of discharge, and temperature conditions.

Yes, if the system includes a backup function (off-grid mode). In that case, the battery automatically switches on during a power outage and supplies the home. Without this feature, the system won’t operate during outages due to safety requirements. We can always include backup capability.

For homes, we recommend an 11 kW or 22 kW smart wallbox that supports integration with solar. Popular options include Easee, Zaptec, ABB, or Wallbox Pulsar Plus. They support remote control, scheduling, and smart charging features.

Using a standard wall socket, a full charge can take 20–30 hours. With an 11 kW charger, a 60 kWh battery charges fully in about 5–6 hours; with a 22 kW charger, about 2–3 hours. A fast charger (50+ kW) can charge to 80% in 30–40 minutes, but those are mainly used on the road, not at home.

Yes! Smart chargers can prioritize energy produced by your solar system. The charger can automatically increase charging power when solar production is high and reduce it when production drops. This maximizes self-consumption and reduces costs.

An 11 kW wallbox including installation typically costs €1500–€2500. A 22 kW charger is usually €2000–€3000. The price includes the device, cables, protection equipment, and installation. If your electrical system needs upgrades, additional costs may apply.

A heat pump is a device that uses a small amount of electricity to move heat. It extracts heat from outdoor air, the ground, or water and transfers it into your home. For every 1 kW of electricity, it can deliver 3–4 kW of heat (COP 3–4). It can heat in winter and cool in summer.

An air-to-water heat pump is the most popular and most affordable choice (€8000–€15,000). A ground-source heat pump is more efficient but more expensive (€15,000–€25,000). Air-to-air (split) heat pumps are great for supplemental heating or cooling (€1500–€4000 per unit). The best choice depends on your home and budget.

Compared to direct electric heating, a heat pump can reduce energy costs by 50–70%. Compared to oil heating, savings are typically 40–60%, and 30–50% versus natural gas. For a 200 m² home, annual heating costs with a heat pump are often around €800–€1500 depending on electricity prices and the building. Combined with solar, savings can be even higher.

Yes! Modern air-to-water heat pumps operate efficiently down to -25°C. Some models can even work at -30°C. On very cold days (below -15°C), efficiency drops, but the pump still provides about 1.5–2x more heat than direct electric heating. Ground-source heat pumps aren’t affected by outdoor cold in the same way.

Yes — it’s an ideal combo. Solar energy can power the heat pump and drastically reduce heating and cooling costs. Smart systems can optimize heat pump operation based on solar production. With a battery, it’s possible to get close to full energy independence.

Send us a request via the contact form, email (info@otso.ee), or call +372 5803 1626. Describe your needs and we’ll send an initial offer within 1–2 business days. After that, we can visit the site for a free survey to provide an accurate proposal.

Yes, from time to time it’s possible to apply for support for renewable energy solutions via KredEx and local municipalities. Subsidies can cover around 15–50% of the investment. We can help you apply and prepare the required documentation. Contact us for the latest information on active support programs.

Installing a solar park takes about 2–5 days, a heat pump 1–3 days, and an EV charger 1 day. Exact time depends on system size and complexity. After ordering, delivery lead time is typically 2–8 weeks depending on equipment availability. We always provide a clear timeline.

We provide a 2–5 year warranty for installation. Typical manufacturer warranties: solar panels 25 years, inverters 5–10 years, batteries 10 years, heat pumps 2–5 years. We also offer maintenance agreements and fast support. All our partners are reputable manufacturers with long-term warranties.