We improved the efficiency of our heat pump by 17%

Summary

Tom shares his experience of living with a heat pump for 18 months, emphasizing its efficiency and comfort during winter. He details how adjustments to setback temperature, heat curve, and hot water settings increased efficiency by 15%. Tom also discusses the impact of a mild autumn on energy use and introduces the concept of degree days to measure heating needs, concluding that despite warmer weather, their energy efficiency efforts were successful.

Takeaways

• 🌱 The speaker and his family have been living with a heat pump for the last 18 months and have improved its efficiency by over 15% this autumn.
• 💡 Their goal is to reduce energy consumption, partly due to cost and to lower emissions, but also in solidarity with Ukraine to reduce reliance on gas.
• 📉 They successfully reduced electricity usage by 13% in October and 23% in November, using 200 kWh less over these two months compared to the previous year.
• 💻 The speaker experimented with the heat pump’s weather compensation curve (heat curve), realizing that frequent tinkering reduced efficiency.
• 🌡️ By raising the setback temperature overnight to 17 degrees (from 15) and lowering the heat curve, they optimized the system’s efficiency.
• 🔧 Heat pumps work best when maintaining a steady temperature rather than large fluctuations, so lowering the heat curve reduced energy usage.
• 💧 They adjusted hot water settings, settling on 48°C when multiple people are home and 42°C when it's just one person, optimizing for their needs.
• 🔍 The speaker also mentioned the impact of a milder autumn, estimating that degree days (used to measure heat demand) were 14% lower in October and 7.5% lower in November.
• 📊 Despite slight variations in electricity usage per degree day, they achieved an 18% efficiency increase overall compared to the previous year.
• 🛠️ They credit the efficiency improvements to lowering the heat curve and optimizing the system’s flow temperature, while still keeping their home comfortable.

Q & A

What is the main focus of the video?

The video discusses the efficiency improvements made to a home heat pump system over 18 months, focusing on how the speaker and their family have optimized their heat pump settings for better performance and energy savings.

How long has the speaker been using the heat pump?

The speaker has been using the heat pump for 18 months and is now in their second winter with the system.

What motivated the speaker to reduce energy consumption?

The speaker was motivated to reduce energy consumption due to high energy costs associated with the price cap, the desire to lower emissions, and solidarity with Ukraine by reducing the use of gas, which indirectly funds Russian aggression.

What was the speaker’s efficiency improvement over the last six months?

The speaker improved their heat pump’s efficiency from 298% to 350%, which led to the system being 20% cheaper to run than their old gas boiler.

What are the three main changes made to the heat pump settings?

The speaker made three main changes: 1) Raised the setback temperature to reduce the difference between night and day temperatures, 2) Lowered the heat curve to improve efficiency, and 3) Adjusted the hot water settings to reduce unnecessary heating.

Why is it important to avoid large temperature swings with a heat pump?

Heat pumps work best when maintaining steady temperatures or making small temperature changes over time. Large temperature swings reduce the system’s efficiency by requiring higher flow temperatures.

What is the ‘heat curve’ and how did adjusting it affect efficiency?

The heat curve is a setting that adjusts the heat pump’s output based on external temperatures. By lowering the heat curve, the speaker reduced the flow temperature, improving efficiency by requiring less energy to heat the radiators.

How did adjusting the setback temperature improve efficiency?

By raising the setback temperature to within 2 degrees of the target morning temperature, the heat pump worked less overnight and didn’t need to use high flow temperatures to heat the house quickly in the morning, which improved efficiency.

What hot water temperatures did the speaker settle on, and why?

The speaker settled on 48°C when multiple people are at home and 42°C when it’s just them, because these temperatures are sufficient for showering and other needs, while reducing the energy required for heating water.

What role did weather conditions play in the speaker's energy efficiency results?

A milder autumn likely contributed to lower energy use, but when comparing kilowatt hours per degree day (a measure accounting for temperature differences), the speaker still saw significant efficiency improvements, particularly in November.