diff --git a/internal/ackhandler/received_packet_handler.go b/internal/ackhandler/received_packet_handler.go
index 6ee66039..b457fb4b 100644
--- a/internal/ackhandler/received_packet_handler.go
+++ b/internal/ackhandler/received_packet_handler.go
@@ -83,14 +83,21 @@ func (h *receivedPacketHandler) GetAlarmTimeout() time.Time {
 }
 
 func (h *receivedPacketHandler) GetAckFrame(encLevel protocol.EncryptionLevel) *wire.AckFrame {
+	var ack *wire.AckFrame
 	switch encLevel {
 	case protocol.EncryptionInitial:
-		return h.initialPackets.GetAckFrame()
+		ack = h.initialPackets.GetAckFrame()
 	case protocol.EncryptionHandshake:
-		return h.handshakePackets.GetAckFrame()
+		ack = h.handshakePackets.GetAckFrame()
 	case protocol.Encryption1RTT:
 		return h.oneRTTPackets.GetAckFrame()
 	default:
 		return nil
 	}
+	// For Initial and Handshake ACKs, the delay time is ignored by the receiver.
+	// Set it to 0 in order to save bytes.
+	if ack != nil {
+		ack.DelayTime = 0
+	}
+	return ack
 }
diff --git a/internal/ackhandler/received_packet_handler_test.go b/internal/ackhandler/received_packet_handler_test.go
index 5938a43c..80a26b7f 100644
--- a/internal/ackhandler/received_packet_handler_test.go
+++ b/internal/ackhandler/received_packet_handler_test.go
@@ -24,24 +24,27 @@ var _ = Describe("Received Packet Handler", func() {
 	})
 
 	It("generates ACKs for different packet number spaces", func() {
-		now := time.Now()
-		Expect(handler.ReceivedPacket(2, protocol.EncryptionInitial, now, true)).To(Succeed())
-		Expect(handler.ReceivedPacket(1, protocol.EncryptionHandshake, now, true)).To(Succeed())
-		Expect(handler.ReceivedPacket(5, protocol.Encryption1RTT, now, true)).To(Succeed())
-		Expect(handler.ReceivedPacket(3, protocol.EncryptionInitial, now, true)).To(Succeed())
-		Expect(handler.ReceivedPacket(2, protocol.EncryptionHandshake, now, true)).To(Succeed())
-		Expect(handler.ReceivedPacket(4, protocol.Encryption1RTT, now, true)).To(Succeed())
+		sendTime := time.Now().Add(-time.Second)
+		Expect(handler.ReceivedPacket(2, protocol.EncryptionInitial, sendTime, true)).To(Succeed())
+		Expect(handler.ReceivedPacket(1, protocol.EncryptionHandshake, sendTime, true)).To(Succeed())
+		Expect(handler.ReceivedPacket(5, protocol.Encryption1RTT, sendTime, true)).To(Succeed())
+		Expect(handler.ReceivedPacket(3, protocol.EncryptionInitial, sendTime, true)).To(Succeed())
+		Expect(handler.ReceivedPacket(2, protocol.EncryptionHandshake, sendTime, true)).To(Succeed())
+		Expect(handler.ReceivedPacket(4, protocol.Encryption1RTT, sendTime, true)).To(Succeed())
 		initialAck := handler.GetAckFrame(protocol.EncryptionInitial)
 		Expect(initialAck).ToNot(BeNil())
 		Expect(initialAck.AckRanges).To(HaveLen(1))
 		Expect(initialAck.AckRanges[0]).To(Equal(wire.AckRange{Smallest: 2, Largest: 3}))
+		Expect(initialAck.DelayTime).To(BeZero())
 		handshakeAck := handler.GetAckFrame(protocol.EncryptionHandshake)
 		Expect(handshakeAck).ToNot(BeNil())
 		Expect(handshakeAck.AckRanges).To(HaveLen(1))
 		Expect(handshakeAck.AckRanges[0]).To(Equal(wire.AckRange{Smallest: 1, Largest: 2}))
+		Expect(handshakeAck.DelayTime).To(BeZero())
 		oneRTTAck := handler.GetAckFrame(protocol.Encryption1RTT)
 		Expect(oneRTTAck).ToNot(BeNil())
 		Expect(oneRTTAck.AckRanges).To(HaveLen(1))
 		Expect(oneRTTAck.AckRanges[0]).To(Equal(wire.AckRange{Smallest: 4, Largest: 5}))
+		Expect(oneRTTAck.DelayTime).To(BeNumerically("~", time.Second, 50*time.Millisecond))
 	})
 })